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COPYRIGHT DEPOSIT. 















Household Bacteriolo 


BY 

S. MARIA ELLIOTT 

INSTRUCTOR IN HOUSEHOLD ECONOMICS 
SIMMONS COLLEGE, BOSTON 




> * 

»> ) 



CHICAGO 

AMERICAN SCHOOL OF HOME ECONOMICS 









COPYRIGHT, 1904 , BY 

AMERICAN SCHOOL OF HOUSEHOLD ECONOMICS 
COPYRIGHT, 1906, 1910, BY 
HOME ECONOMICS ASSOCIATION 

Entered at Stationers Hall, London 
Ail Rights Reserved 


• % 
• « 
t 1 « 
« 


CCI.A268282 


CONTENTS 


Letter to Students , . , , . v 

Dust i 

Dust-Gardens . . . « . , 7 

Dust Plants . . . , . . 15 

Bacteria . . . , ,16 

Molds ....... 33 

Yeasts . ....... 3 g 

Work of Bacteria ..... 47 

Butter Making ...... 57 

Cheese ....... 58 

Vinegar ....... 60 

Harmful Dust Plants ..... 63 

Preserving Food . . . . . .69 

Disease Germs ...... 75 

Resistance of the Body . . . . .86 

Sanitation . . . . . . 96 

History of Bacteriology . . . .109 

Summary . . . . . . .113 

Extracts from the Instructor’s Note Book . 117 
Safeguards of the Body Against Disease, by 

T. Mitchell Prudden . . . .127 

Bibliography . . . . . 153 

Supplemental Study Outlines . . . .157 

Index ....... i 63 







AMERICAN SCHOOL. OF HOME ECONOMICS 

. . •. 

CHICAGO 


January I, 1907. 


My dear Madam: 

In beginning our work in Household 
Bacteriology together I should like to make a few 
suggestions as to aims and methods of study. 

The aims to be reached in the study of any 
science are at least two—a knowledge of its un¬ 
derlying principles and as thorough an application 
of those principles as is possible. r 

For the principles you will consult the lesson 
booklets. From them, too. you will get suggested 
applications, but the subject 7/ill not become a 
part of yourself until you recognize new applica¬ 
tions many times a day. It is 3aid that no person 
KNOWS a foreign language until he can think in 
that language. In a similar way you will want to 
think these facts into your life and work. 

Suggestions for study have already been given 
to you. I hope that you may be able to try all of 
the experiments suggested;_at least make a "dust 
garden" as described. If you can get no suitable 
dish, a regular Petri dish may be obtained through 
the School for 30 cents and a tube of prepared 
"nutrient gelatine".for 20 cents. The dish may 
be returned. Also, I hope that you will read some 
of the books recommended in the bibliography. 

* 

The facts of bacteriology underlie so firmly 
all our daily living that there is no need to go 
far afield for illustrations. But a thorough 
knowledge of the science can be gained only through 
laboratory methods and with a microscope. There¬ 
fore, I hope you may be able sometime to supple- 


ment this study by microscopic work. Perhaps 
through the aid or some doctor or other scientist 
you may be able now to get a peep into this world 
of the unseen. 

If these les'sons point out dangers of which 
you were before unconscious, they also suggest 
ways of escape from those dangers. You will gain 
some knowledge of the causes of waste and disease 
If this leads you to efforts for the prevention 
and removal of such causes, *the result will be 
those healthful conditions which make the most 
effectual safeguard against the attacks of the 
few micro-organi3ms that are our foes. 

I hope the relations between hygiene and some 
of the daily tasks of housekeeping will gain a 
deeper significance in your mind; and this ele¬ 
mentary study may result not only in pleasure and 
profit to you, but also, through you, in better 
conditions of healthful living for others* 

Sincerely yours. 



Instructor 


































































































. 
















- 
















































































0 



SIMMONS COLLEGE, BOSTON, MASSACHUSETTS 












HOUSEHOLD BACTERIOLOGY 


M OST persons now know that mankind is greatly 
troubled by the work of certain minute agents 
—variously termed germs, bacteria, micro-organ- 
isms. Few, however, realize the good that these 
forms do, or understand them and their place in the 
. world. It is the purpose of the following pages to 
show the relations, both good and evil, that bacteria . 
and other micro-organisms bear to the household. 

DUST 

♦ 

Most housewives look upon dust as an undesirable Prevalence 
thing that they are constantly seeking to be rid of. If ° f Dust 
dust is seen on the piano or on the table each thinks 
she will be considered a slack housekeeper. Perhaps 
some are not troubled by the presence of dust that does 
not show. Such fight the enemy vigorously where vis- : 
ible, .but relax effort where or when he is invisible'. 

The temptation comes to hide the tell-tale dust by 
shutting out light. 

Few persons there are who have not at some time 



2 


HOUSEHOLD BACTERIOLOGY . 


exclaimed, “Where does all the dust come from?” If 
a house be thoroughly cleaned from cellar floor to attic 
ridge, tightly closed for months or years, when re¬ 
opened dust will be found in great quantities. 

This is true even in the country, where perhaps a 
single house, removed from the highway, stands sur¬ 
rounded by grass and trees. 

The “housekeeping” of ships includes dusting. 
The officers’ quarters of the government ships are 
dusted regularly, although land may not be seen for 
months at a time. 

Dust-proof Scientists have tried to get a dust-proof room or 

Room or .... . . 

House house in which to carry on their experiments. This 
has required attention to location and site, that there 
should be no jar from traffic or vibration from winds; 
a careful preparation of the surrounding soil; numer¬ 
ous walls separated from each other and made largely 
of glass, carefully joined and hermetically sealed. The 
air admitted must be freed from its dust; all clothes 
ordinarily worn by the experimenter must be ex¬ 
changed for garments especially prepared and cared 
for, before he enters this to-be-dustless room. Even 
then all surfaces need to be slightly moist, that any 
stray speck of dust which has escaped all these guards 
may be caught and held. 

Necessity Such conditions as these can never be secured in 

of Dust 

ordinary life, so that dust will probably be present with 
us always. Indeed, it is probable that were all dust 
exterminated, life also would become extinct, for life 
in its most efficient forms needs light, and Tyndall 


DUST. 


3 


proved by delicate experiments that when all dust was 
removed from the track of a beam of light, there was 
darkness. So before the command, “Let there be 
light,” the dust condition of light must have been pres¬ 
ent. Balloonists find that as they ascend higher the 
color of the sky deepens. At a distance of some miles 
the sky is nearly black, there is so little dust to scatter 
the rays of light. If the stellar spaces are dustless, 
they must be black, and therefore colorless. The mois¬ 
ture of the air collects about the dust-particles, giving 
us clouds, and with them all the glories of sunrise 
and sunset. Fogs, too, are considered to be masses 
of “water-dust,” and ships far out at sea have had 
their sails colored by this dust while sailing through 
banks of fog. 

Astronomers find meteoric dust in the atmosphere. 
When this falls on the snow and ice fields of the Arctic 
regions it is readily recognized. The eruption of Kra- 
katoa proved that volcanic dust is disseminated world¬ 
wide. 

An old writer has said: “The sun discovers atomes 
though they be invisible by candle light, and makes 
them dance naked in his beams.” 

Thus dust, just common every-day dust, is a very 
important and complex substance, which promises 
much of interest in its study. Therefore, again we ask 
where does it come from and of what is it made ? 

When a March wind blows over a sandy road or a 
November gale sweeps through city streets, it is evi¬ 
dent that a large part of the dust found in the house 


Meteoric 

Dust 


Source 
of Dust 


4 


HOUSEHOLD BACTERIOLOGY. 


Ingredients 
of Dust 


Movements 
of Dust 


comes through open doors and windows. Few win¬ 
dows and doors are so tightly fitted that fine dust will 
not sift in round their casings. 

Until electricity is made the common source of heat 
and light, there will be much dust from coal and wood, 
both before and after they are burned. These sources 
are too evident to need more than a mention. It is 
from the wear and tear of the house itself, its finish and 
furnishings, from our own bodies and the clothing that 
covers them, that the larger amount of dust comes. 
From these we have bits of wood, stone, cotton, hair, 
dead cells from all animal bodies—a mass of mineral, 
animal, and vegetable matter of very complex compo¬ 
sition. 

Since time began, everything in this old world has 
thus been wearing away more or less slowly, adding 
bit by bit to similar accumulations, until what we 
know as soil has been built up—pure mineral soil made 
from the debris of the rocks; organic soil or loam from 
the addition to this mineral soil of vegetable and ani¬ 
mal debris. The same processes are continually going 
on all about us. 

The dictionaries recognize this process when they 
tell us that dust is “Earth or other matter in fine dry 
particles so attenuated that they can be raised and car¬ 
ried by the wind.” 

Winds then are the responsible agents for much of 
the dust in our houses, but wind is simply air in mo¬ 
tion. We cannot walk across the floor, make a bed, 
rock comfortably in a chair, or dance a jig without 


DUST. 


5 


making some wind currents. If dust is present in this 
current, it will be stirred up to settle back, where it 
was before, or to be blown to some other place. The 
more dust or the stronger the wind, the surer it is that 
the dust will be carried along with the current. 

But why should the housewife spend so much energy 
and time in trying to keep her house free from dust? 
All the dust elements we have seen so far are no.t likely 
to do her much harm. The ashes or other mineral dust 
may scratch the polished table or the brass ornaments 
and silverware, but not so long as it lies quiet. It is 
the moving grain of sand, not the still one, that 
scratches. The other ingredients, bits of dead animal 
or vegetable matter, may be disagreeable to think of, 
but they are of the same stuff as ourselves, our clothes, 
our furniture. If this dead matter were all there is 
to dust, no one would ever have heard of the science 
of bacteriology. 

Many of the daily occurrences in the home give 
rise to questions which may be readily answered if we 
will but turn our kitchens into laboratories and try 
some simple experiments. 

Perhaps you forgot to change the water in a vase of 
flowers and it stayed there a week. How did it smell 
when you poured it out? How did the stems that had 
been in the dirty water feel? 

Possibly when you left home for a week’s visit last 
summer, you knew the ice was all gone from the refrig¬ 
erator, but you forgot to empty the pan underneath. 


Why Keep 
Free From 
Dust 


Familiar 

Experiences 


Leavened 

Bread 


Mold 

Mildew 


6 HOUSEHOLD BACTERIOLOGY . 

What did you find on your return? A slimy film over 
the surface of the water, did you not? 

Such experiences may be familiar to all. A few 
years ago these changes were thought to be due to the 
oxygen of the air, which in some way, under certain 
conditions, made some things sour, some bitter, and 
others putrid. 

In the days of our grandmothers much of the 
bread was made with leaven like that used in Bible 
times—a mixture of flour and water exposed to the 
air and whatever the air contained. This was called 
“barm.” Such bread is still common in some parts 
of our country, and known as “salt-rising bread,” 
and the barm when made with milk is called “milk 
emptins.” 

In the old days a portion of the leavened mass 
was kept to start the next batch of bread. Occa¬ 
sionally this was forgotten or it spoiled, then the 
housewife borrowed from her neighbor, as when the 
fire on the hearth was out, a coal was borrowed. 
Sometimes now the yeast raised sponge becomes slight¬ 
ly sour before it is ready for baking. Why ? 

Apple or other sauces containing sugar ferment 
or sour and the housewife scalds them. This may 
make them as palatable as when freshly stewed. Yet 
they often turn sour again and, after a while, scalding 
or even boiling does, not remove the sharp or sting¬ 
ing effect upon the tongue. 

The moist bread in the jar is found specked with 
mold; some August morning the sprinkled clothes 


DUST GARDENS, 


7 


in the laundry basket are mildewed; the “best room,” 
seldom used and darkened by drawn shades and tight¬ 
ly closed blinds, becomes musty. 

What do all these things mean, or have they any re¬ 
lation to each other? 

We will now see if we can answer these questions. 

Experiment I. Mix a little yeast with some sweet¬ 
ened water and let it stand in a warm place where the 
temperature is from 70° to 75 0 Fahr. Put a few table¬ 
spoonfuls of beef broth or molasses water into a cup 
or bottle and leave it uncovered in the kitchen where 
it will be warm. Watch carefully what happens. Be¬ 
fore long bubbles show on the surface of the sweetened 
water; perhaps you may see bubbles rising in the broth. 
If left long enough the sweet liquid will be sour and 
the good broth smell bad. You say the one has fer¬ 
mented, the other is putrid. What has made the 
change? You did not add anything to the mixture; 
you only kept it warm and uncovered. 

DUST GARDENS. 

Experiment II. From any dealer in laboratory sup¬ 
plies or through the doctor or druggist get a Petri dish 
or plate. This is simply two round glass dishes, one- 
quarter to one-half inch in depth, one just large enough 
to fit over the other as a cover. See Fig. 1. This ex¬ 
periment can be made without the Petri dish, although 
not so conveniently, as follows: 

Take a clear glass sauce dish or a finger bowl. Fig. 
2. Cover with a piece of smooth, thin glass clear 


Experiments 
with Dust 


The Garden 
Plot 


8 


HOUSEHOLD BACTERIOLOGY. 


enough to see through readily and large enough 
to entirely and tightly cover the dish. After 
washing well, place both together in a pan in a cool 
oven and gradually raise the temperature until it is hot 
enough to bake bread or to yellow a piece of white 
paper in half a minute. Let them bake for an hour 
or more. Then open the oven and place the pan 
where the dish may cool slowly. When cold take 
out, without removing the covering plate, and put 
round both dish and plate a strong rubber band, or tie 
them together with a string. 

This we will call our garden-plot. But a garden is 
of little use without something growing in it, and for 
this soil is required. 



FIG. 1. PETRI DISH FOR PLATE CULTURES. 

For the soil take the following recipe: Chop finely 
one-quarter pound of lean, juicy beef. Mix this with 
one cup of warm water. Heat in double boiler, stir¬ 
ring often until water in water pan has boiled fifteen 
minutes. Remove inner dish, place directly over the 
fire and allow broth to boil ten or fifteen minutes. 
Clear by straining through two or more thicknesses of 





































DUST GARDENS. 


9 


flannel wet in cold water. Squeeze the meat carefully 
to get out all its juices but not much fat. The meat 
is acid, therefore, add from one-eighth to one-quarter 
teaspoonful of bi-carbonate of soda. Replace the water 
lost through evaporation. 

Moisten three heaping tablespoonfuls of finely di¬ 
vided gelatine in a very little cold water and add to 



FIG. 2. SHALLOW BOWL COVERED WITH SHEET OF GLASS. 


the boiling hot broth. When the gelatine is dis¬ 
solved, strain through hot flannel. 

Put three or four tablespoonfuls of the broth into 
each of several small bottles. Plug the mouth of 
each with a close wad of cotton wool or tie over each 
a thick mat of the same. For three successive days 
place the bottles on a piece of folded cloth in a pan of 
cold water and boil them fifteen minutes. 

Gelatine melts at quite a low temperature, so if the 
dust garden is prepared in summer it may not re¬ 
main solid. If kept in a very warm place in the 
room it may melt at any time. A better substance 
to use for the jelly is agar, which remains solid at blood 
heat, 98.5° Fahr. . This may be found in some cities 
at the druggists’, or at the dealers in chemical or bac¬ 
teriological supplies. It solidifies suddenly, if its temper- 
ture drops below a certain point, and as it is rather 


Preparing 
the Soil. 





10 


HOUSEHOLD BACTERIOLOGY . 


difficult to prepare, the gelatine is more favorable for 
the amateur’s use.* 

In our garden we want only certain kinds of plants,, 
and we want to know just where they come from, we, 


Planting 
the Garden 



therefore, bake the dish and boil the jelly until sure 
that nothing in either is alive. 

When ready to plant the garden, put the bottle of 
jellied beef juice into a dish of cold water. Heat this 
until the jelly is melted and then cool slightly. 


*For the careful, accurate preparation of such soil, consult 
“Laboratory Work in Bacteriology,” Frederick G. Novy, or 
any other manual of laboratory practice in Bacteriology. 

A Petri dish may be obtained from the School for 30c 
and a bottle of agar ready for use for 24c (in stamps) sent 
postpaid. 

tThe “Story of Germ Life,” H. W. Conn; D. Appleton & 
Co., Publishers. 



DUST GARDENS. 


ii 


Remove the elastic from the dish. When the 
tube or bottle of jelly is cool enough to he held in 
the hand, remove the cotton wool plug or stopper, 
carefully raise the cover of the dish on one side, just 
enough to insert the mouth of the bottle. Pour the 
melted jelly into the dish, cover, and gently turn with 
a circular motion until the jelly is spread evenly over 
the bottom of the dish. Replace the elastic and let 
the jelly harden. 

The garden is now ready for planting. To do this, 
all that is necessary is to remove the cover and leave 
the dish open for from twenty to thirty minutes. If 
opened in a very dusty place, expose only ten min¬ 
utes. Do not go near or meddle in any way. At the 
end of the time replace the cover and the elastic band. 
Let the dish remain in a warm room not above 70° F, 
and watch carefully for whatever happens. 

In the course of thirty-six to forty-eight hours or 
longer, minute light-colored specks will show on the 
surface of the jelly. These will be seen to grow 
larger, to become of different colors—pink, yellow, 
orange, green, blue, possibly a deep red. 

Some spots will be shiny, smooth, and round; oth¬ 
ers branched like mosses or seaweeds; others with 
white rims and dark centers, showing a pile like 
velvet, and, when seen through the sides of the dish, 
they may suggest minute pins with ball heads. Fig. 3. 
All of these forms may not show themselves, but in 
most cases there will be seen the shiny, smooth spots, 


Growth of 
the Garden 


Putrefaction 


12 HOUSEHOLD BACTERIOLOGY. 

and the hairy or velvety ones. Look at the garden 
through a magnifying glass, if possible; watch every 
change; write down an accurate and full account as 
to time, appearance, conditions of temperature, light, 
etc. Then change the conditions. Put the dust- 
garden into the refrigerator, shut it into a box, etc. 
See how the colonies are affected by each new condi¬ 
tion or by any two combined. 

If a compound miscroscope can be used, touch the 
point of a needle to pne of the spots and place the 
speck of matter taken up on a clean glass slide. Put 
on a drop of cool boiled water, and over this a 
cover glass; examine carefully for shape and motion; 
draw what is seen. In this way examine the differ¬ 
ent colonies to see if the forms in all are of the same 
shape. 

Let the dust garden grow for a week or more, then 
gently raise the cover, smelling of the contents, and 
as v this is done, if the growth is sufficiently far ad¬ 
vanced, there will be sensible proof that dust-plants 
may cause putrefaction. The next time you are 
tempted to leave a piece of meat exposed, remember 
the dust-garden, and cover the meat with a cloth to 
keep out dust. 

Figures 4 and 5 are photographs of such dust-gar¬ 
dens after more than two weeks’ growth. The prin¬ 
cipal colonies of molds are marked a, and those 
marked b are colonies of bacteria. In Fig. 5 the row 
of cdlonies marked b' shows well how thickly they 



FIG. 4. PHOTOGRAPH OF A DUST GARDEN AFTER TWO WEEKS 

GROWTH. 

Colonies of Mould Marked a ; Colonies of Bacteria not Marked. 


i 


• 








DUST GARDENS. 


13 


sometimes crowd together. Probably these were all 
attached to some tiny fibre of wood or cloth. 

The soil or “nutrient gelatine” in our experiments 
had beef juice in it; you will ask if any other soil 
would do. The gardener knows that his pinks will 
grow better in one place and his ferns in another be¬ 
cause each requires or likes, we may say, a particular 
kind of food which that soil contains. 

In the laboratory numerous soils or nutrient media 
are used—milk, potato, beer, blood-serum, etc. 

A moment’s thought will show that all the food 
substances which we like best are subject to changes 
which in general we designate as “spoiling.” Some 
grow bitter, some sour, some odorous, some rancid. 
In a few cases this result is due to processes brought 
about by mere chemical changes—that is, without the 
intervention of any living agent or ferment; but in 
most cases where food spoils, it is due to the growth 
on or in the substance itself of the little plants, which 
have been carried to it through ordinary dust. 

The milk in the pantry is found to be sour. When 
it was secreted by the milk gland in the cow’s body it 
was sweet and pure. It passed down into the milk 
duct in its passage outward, and here perhaps it met 
a few of the dust-plants which had passed into the 
mouth of the duct from the outside. Hundreds, no 
doubt, fell into the pail from the dusty air of the stall 
the cow’s hairy coat, the milkman’s clothes, or hands, 
or hair, even from the pail itself, for all are more 


Kinds of 
Soil 


Souring 
of Milk 


14 


HOUSEHOLD BACTERIOLOGY . 


or less dusty. Among these hundreds of forms are 
some that like the sugar of the milk as food. While 
feeding upon this, they change a part of it into acid- 
lactic acid. When this acid reaches *a certain amount, 
it coagulates the casein of the milk. 

Production The cleaner the milk, the fewer of these lactic acid 
.actic Acid producing plants will be present and the longer the 
milk will keep sweet. Cold retards their growth. 
Milk should then be cooled as quickly as possible 
after being drawn from the cow, and should be kept 
in a cold place at all times. 

Milk is a most favorable culture ground for bac¬ 
teria because it has some of all classes of food ele¬ 
ments, being what is known as a perfect food. Its 
opaqueness hides much of the solid dirt which not 
only seeds it with bacteria but adds certain soluble 
matters. Too often the dirty character of the milk is 
known only by sight of the actual dirt at the bottom 
of the empty glass. 

The possibilities in the way of clean milk, which 
means safe milk, were forcibly illustrated by exhibits 
from some American “model dairies” at the Paris Ex¬ 
position in 1904. Milk and cream in a perfectly fresh 
condition were shown after a journey of ten days; the 
only treatment being extreme cleanliness in milking, sta¬ 
ble, receptacle, etc., and cold. A glass of ordinary, un¬ 
clean milk contains millions of bacteria, which al¬ 
though harmless to a vigorous adult are the cause, di¬ 
rect or indirect, of the death of thousands cf young 
children annually. 



FIG. 5. A DUST GARDEN. 

(a) Colonies of Mould. (b) Colonies of Bacteria. 

(b'> Colonies of Bacteria oq a Thread, 










V 













' 


DUST PLANTS . 

DUST PLANTS 


IS 


We have seen from the dust-garden that dust does 
contain living plants which, when they find food in a 
moist, warm place, will grow and multiply. 

They were not seen when they settled out of the 
dust on the jelly, and not until they had reproduced 



% 


Fig. C. (a) One Colony of Bacilli or Rod-Shaped Bacteria as Seen In 
“Dust Garden.” Highly Magnified. 

(b) Eight Bacteria from the Colony, Magnified Much More. 

(After Pruddeu.) 


Colony of 
Dust Plants 


themselves many times, so that a “colony” was formed, 
were we able to see that anything had been planted 
in the dust garden. But each colony or spot shows 
where a single plant dropped on the gelatine; the spot 
becomes visible only after it contains thousands of in¬ 
dividuals, which are kept close together by the gelatine. 


Names of 
Dust Plants 


16 


HOUSEHOLD BACTERIOLOGY. 


All of these dust-plants have to be studied under' 
the microscope and are therefore called micro-organ¬ 
isms . Microbe —a name given by Louis Pasteur— 
which from its derivation would include all, has 
come gradually to be applied to one class, the bac¬ 
teria. Still a third word, germ, which really means 
the beginning, or that first living cell which produces 
a more complex form, is becoming restricted to the 
micro-organisms that cause disease, as the germ of 
tuberculosis, the germ of typhoid fever, etc. All 
~ these names may apply to micro- 

w scopic animal forms as well.- . Strict¬ 

er w jy speakings a p dust-plants are germs, 
all are microbes, all are micro-organ¬ 
isms. 

The “garden” will show two 
kinds of plants and sometimes a 
third, although this is not so com¬ 
mon in house dust. We will now 
see what these three kinds of plants 
are, two of which we may expect 
to find in all houses at anv time. 





Fig. 7. Typical 
Forms of Bacteria. 

(a) Cocci, or Ball 

Forms. (hj Bacini, Ti le third, wild yeast, would very 

or Rod-shaped ’ J * J 

Forms, or 4 likely be caught if we planted our 
Forms - dust garden under the apple trees in 

summer time. 

BACTERIA 

Let us find out first what the plants are like which 
make the smooth, glossy, shiny colonies, whether round 
or radiate. These are the bacteria, and each colony 


BACTERIA. 


1 7 


has come from the reproduction of one parent—a 
bacterium. Fig. 6. 

Under the microscope these bacteria show three 
principal shapes. Fig. 7. One like a short, round 
stick or rod, is called a bacillus and bacilli for the 
plural. Fig. 7b. Another is ball-shaped, called coccus 
or cocci for the plural (the third c sounding like s). 
Fig. 7a. A third form which resembles one turn or 
more of a screw is called a spirillum 
or spirilla for the plural. Fig. 7c. 

These typical forms may shade 
into each other. The bacilli may be 
long or short, with pointed, blunt, 
or square cut ends. They may be so 
short and plump as to closely re¬ 
semble a coccus. Fig. 8. The spi¬ 
ral forms may curve very little or 
have decided and numerous twists. 

Fig. 9. 

Bacteriologists do not always agree 
as to which class a newly found indi¬ 
vidual should belong, and to the housewife it makes 
no difference. 

The bacteria are so simple in structure and so diffi¬ 
cult to study that there is little to describe. Each 
consists of a single cell, so far as is known. This 
seems to have a denser portion on the outside, which 
forms a cell wall and may be cellulose as in the higher 
plants. 

This simple cell of protoplasm or “foundation stuff” 



Fig. 8. 'Bacilli or 
Rod-shaped Bacte¬ 
ria. 


Shape of 
Bacteria 


Structure 

Bacteria 








Excretions 
*i Bacteria 


18 HOUSEHOLD BACTERIOLOGY . 

is endowed with all the characteristics of living matter 
anywhere. 

All living things whether plant or animal take 
food in some way. All, too, having taken food, 
change it over into their own substance and give out 



some of the results of these changes as waste prod¬ 
ucts in the form of gases, liquids, or solids. 

Bacteria are no exception to this universal rule. 
Their products are either gases or liquids and these, 
dissolved in blood or other liquids, bring about vari¬ 
ous changes, the results of which may be either de¬ 
sirable or undesirable, according to the nature of the 
bacterium, the amount of the excretion, or other con¬ 
ditions under which the changes are wrought. 

The processes of bacterial growth in the human 
body and in food substances are similar. 



BACTERIA . 


19 



The excretions of the bacteria in milk, fish, etc,, 
may produce changes which, very apparently, ren¬ 
der them unfit for food, or the changes may not be 
apparent. If food containing these excretions be 
eaten, or if the bacteria grow in the body itself, the 
excretions may bring about abnormal conditions more 
or less severe, but all may be called disease. 

Like the mag¬ 
gots in cheese or 
the clothes moth 
larva, the bacteria 
live surrounded by 
their food supply 
and they have only 
to take, digest, and 
absorb it as need¬ 
ed. Like these animal forms, they feed upon com¬ 
plex organized food which has been previously pre¬ 
pared by other plants or animals. In this they differ 
from most plants which must manufacture their food 
out of the mineral and other inorganic substances in 
air, water, or soil. However, some species can do 
this although they have not the green coloring mat¬ 
ter or chlorophyll cells which in the higher plants are 
the food factories. 

Because of this power of living on inorganic sub¬ 
stances, which no known animal possesses, the sci¬ 
entists have decided that these micro-organisms must 
be called plants rather than animals. 

Bacteria have no leaves, roots, stems, or any or- 


A BACILLUS DIVIDING INTO 
TWO GENERATIONS. 


Bacteria 
are Plants 





20 


HOUSEHOLD BACTERIOLOGY . 


Food of 
Bacteria 


&€ production 
of Bacteria 


gans like higher plants. They are simply transpar¬ 
ent bits of jelly-like protoplasm. 

Bacteria in general like the same kinds of food that 
man likes, although they do not require the variety 
in diet which to civilized man seems necessary. 

Some flourish best in 
meat juices, others in 
milk, some in starchy 
foods, others in su¬ 
gary solutions, while 
still others enjoy best 

Fi«k 11.. teiffgrcBt Forms of Bacilli. the fats. 

(a) Simple, detached forms. 

(b) Chains of united bacilli. They alsQ s p ow> p ke 

man, a surprising faculty of adaptation. If unable to 
get their favorite food, many will grow on whatever is 
at hand. Any organic substance which is not absolutely 
dry may becorpe food for some species of dust-plants. 
Dust-plants will not leave the moist surfaces upon 
which they fall, but where such surfaces become dry, 
then the plants are ready to be blown into the air by 
winds or carried along on anything which touches 
them. 

Ordinarily dust particles are probably never so dry 
that the bacteria or other micro-organisms clinging to 
them are killed. 

All bacteria reproduce by division of the parent 
into halves, which process is called fission. Fig. io. 
Sometimes these daughter cells remain attached even 
after they themselves have divided into two. A 



BACTERIA. 


21 


chain of cells results so that what looks under the 
microscope like one individual may be three or more 
generations. Fig. n. 

The ball forms divide in the same way along a di¬ 
ameter. Some, however, divide in more than one di- 




FIG. 12. REPRODUCTION OF COCCI BY FISSION. 

(a) Division into two. (c) Division into four. 

(b) Chains of cocci. (d) A sheet of four cocci. 



rection, so that the colony of daughter cells may 
touch at one side only, like closely strung beads, or 
on two sides, making a sheet or film of cells, or they 
may become piled upon each other like a cube of 
marbles. Fig. 12. 


22 


HOUSEHOLD BACTERIOLOGY. 


Rapidity 
of Growth 


The spiral forms also may remain in one colony or 
break up into single cells after division. 

Sometimes they 
unite their bodies 
by a gelatinous 
film to form a 
slime over the sur¬ 
face of whatever 
they are growing 
upon, as seen on 
the walls of the waste pipe of the refrigerator or on 
the surface of the water in the pan. This is known 
as a zoogloea form. Fig. 13. 

The rapidity with which they reproduce depends 
largely upon the food supply, the warmth and moist¬ 
ure—that is, whether the conditions of life and 
growth are favorable. 

In this prolific reproduction lies their great power 
for harm or benefit to the world. 

In some species, under favorable conditions, a new 
generation is born oftener than every half hour. If 
this rate were continued for a day, one bacterium 
might become ancestor of over sixteen million de¬ 
scendants. Some interested observer has calculated 
that in two days the billions thus born would fill a 
pint measure and weigh a pound, while in another 
twenty-four hours their weight would equal eight 
thousand tons. 

These numbers, however, are of no practical im- 



FIG. 13. ZOOGLOEA OR THE 
FILM-FORMING BACTERIA. 


BACTERIA. 


23 


portance, for long before such a population was 
reached the food supply would be gone or the parent 
forms would be killed by their own excretions. Here, 
as in the animal world, if the wastes of living accu¬ 
mulate, death results. Yet wherever conditions of 
moisture, warmth, and food remain favorable they 
will multiply with almost infinite rapidity. 

Botanically the bacteria belong to the fungi, and 
because they reproduce by fission or breaking into 
two, they are called Schizomycetes or Fission Fungi. 

A string of sausages, often seen hanging in the win¬ 
dows of a market, is a fair representation, except in 
size, of a chain colony of bacteria. 

Take a piece of white rubber tubing, ten to twelve 
inches long and from one-half to one inch in diam¬ 
eter. Tie it tightly at one end with waxed thread. 
Fill this about three-quarters full of water and tie 
the second end so that no water may escape. From 
thread to thread will represent very well a bacillus. 

Divide this in the middle by a rubber band and two 
generations are represented or a chain colony of two 
individuals. The same method may be continued to 
show the future reproduction processes. 

Their minute size would seem to indicate insig¬ 
nificance, but they make up in energy, in the work 
done, and in numbers, for all that is lacking in size. 
Not one is ever visible to the naked eye, while some 
can be seen only with great difficulty by the skilled 
observer and under the most powerful microscope. 

They are so small that little idea of their size can 


Bacteria 
Are Classed 
as Fungi 


Size of 
Bacteria 


24 


HOUSEHOLD BACTERIOLOGY . 


Relations 
to Oxygen 


be obtained by actual measurement, only by compari¬ 
son. Fig. 14 represents the largest bacterium known 
magnified six hundred diameters. One twenty-five 
thousandth of an inch is not an uncommon length for 
a bacterium. 



Bacillus 
Megatherium. 

(a and b) Individ¬ 
uals. 

(c and d) Two indi¬ 
viduals, each di¬ 

viding into halves. 


Yet, small as they are, they are heavier than air, 
and therefore settle out of it when 
it is still. 

It is estimated that in the space 
occupied by a grain of sugar there 
might be packed six hundred mil¬ 
lions and each bacterium be com¬ 
fortable. Compared with the bac¬ 
teria which may lodge there, the 
wrinkles in the skin of our hands 
are like ditches six or eight feet 
deep. No wonder that it is diffi- 
* cult to dislodge them by any ordi¬ 
nary washing. The surgeon has to resort to a strong 
soap, vigorous brushing, and the use of numerous 
bacterial poisons in addition to the ordinary washing, 
before he is sure that these valleys are not rich in the 
tiny plants that might bring suffering or death to his 
patient. 

Most of the bacteria require oxygen to breathe, as 
we do, but some can live without air. Some will ac¬ 
commodate themselves to any condition. Preferring 
much or little oxygen, they will, however, grow under 
the opposite condition, if they must. 


BACTERIA . 25 

Of course, the disease germs which grow in the in¬ 
terior of our bodies flourish best under conditions of 
darkness and lessened air supply. Out-of-door life, 
then, is a preventive measure, and next to this is a 



FIG. 15. SUNSHINE AS A DISINFECTANT. (After Lefar.) 
Under the letters of black paper there was growth; in the remainder 
of the plate the sunlight killed the bacteria. 


generous supply of sunlight and fresh air inside our 
houses. 

Experiments have shown that the disease germs 


Disease 

and 

Darkness 










2(5 


HOUSEHOLD BACTERIOLOGY . 


Effect of 
Sunlight 


Power of 
Movement 


live much longer when grown in a cellar than when 
cultivated in the light rooms of a house. 

All disease germs, so far as known, are killed by 
direct sunlight. This was proved some years ago 
by planting a Petri dish with typhoid fever germs. 
Half of the dish was covered with black paper, while 
the uncovered half was exposed to direct sunlight. 
On the sunlighted half no growth appeared, while 
the other half showed many colonies. A similar ex¬ 
periment is illustrated by Fig. 15. 

In this experiment the letters of the name “Ty¬ 
phus” were cut out of black paper and placed on the 
under side of the cover of a Petri dish which had 
been planted with bacteria. The dish was exposed 
to sunlight for an hour and a half and then left in a 
dark room for twenty-four hours. When the paper 
letters were removed, the space covered by them was 
found thickly studded with the minute colonies of 
bacteria. The rest of the plate showed no appearance 
of bacterial life. 

Some bacteria, like most of the higher plants, re¬ 
main stationary, having no power of motion, while 
others move by slow or jerky, worm-like contrac¬ 
tions. Still others are moved about by whip-like ex¬ 
tensions of their bodies, called flagella or* cilia. Some 
have only one whip at one end of the body, others 
one or a cluster at each end, while others have them 
reaching out from all parts. Fig. 16. 

Some bacteriologists place all the forms which have 


BACTERIA. 


27 


flagella in one species— Bacillus, and all without 
flagella in another species— Bacterium. 

When for any reason there comes a period of hard Spores 

times in the life history of the bacteria, such as cold, 
dryness, or lack of food, some bacteria have the 



(a) A flagellum at one end. 

(b) A flagellum at each end. 

(c, d. and e) Tufts of flagella in different positions. 

(After Conn.) 

power of contracting their bodies into smaller space, 
possibly drawing it all into one end or from the mid¬ 
dle into each end. Fig. 17. This is called the spore 
stage. These spores can weather great extremes of 
famine or cold or resist the action of strong chem¬ 
icals. Some can be frozen, others boiled and still re¬ 
tain life. When good times return in the form of 




Resistance 
of Spores 


Dust Plants 
in the 
Refrigerator 


28 HOUSEHOLD BACTERIOLOGY. 

moisture, warmth, or more food, the resting, resist¬ 
ant spore starts into growth again and continues its 
life as before. 

The species that do not form spores are much 
more easily killed. Those that form spores readily, 
being difficult to kill, are more likely to cause dis¬ 
ease or destruction of property. Fortunately for us, 
most of the disease or “pathogenic” germs do not 
form spores readily, if at all. It is these spores that 
make necessary the repeated “scalding” by which the 
housewife tries to save the food which she finds spoil¬ 
ing. 

The lowest temperature known will not kill some 
bacteria, while some varieties in the spore state will 
resist the temperature of boiling water. Indeed the 
heating sometimes seems to favor their changing into 
the active state. 

Dust readily finds access to the ice box or the refrig¬ 
erator, even if the ice is thoroughly cleaned before it is 
put in. The dust-plants will grow on any bits of food 
carelessly dropped and by their gaseous products may 
taint the meat, milk, and other foods. The escape pipe 
of a refrigerator needs to be often and carefully 
cleaned throughout its entire length, else it will be 
covered with a slimy mass of bacterial erowth. Many 
of the bacteria found here are the germs of putrefac¬ 
tion. 

This pipe may be cleaned with a swab of cloth or 
sponge tightly wrapped around a long stick, rat¬ 
tan or whalebone, with a small, long-handled brush, 


BACTERIA . 


29 


or if the pipe is too difficult of access for these 
methods, a boiling hot solution of washing soda may 
be poured down once a week, or when the ice box is 
empty. 

The pan under the refrigerator should be scrubbed 
carefully with hot soapsuds or scalded with the wash- 



FIG. 17. VARIOUS SPORE BEARING BACTERIA. 

(a) Spores Escaping from Ruptured End. (After Conn.) 


ing soda, that no slime may appear. The escape 
pipe, too, should be opened to the air and in a place 
where the air will be pure. 

The housewife who allows her refrigerator pipe to 
empty directly into a hole in the cellar floor, un¬ 
derneath which is a slimy mass of muddy filth, need 
not be surprised that milk and butter do not “keep 
well.” 






Boiling 

Clothes 


Natural 
Home of 
Bacteria 


30 HOUSEHOLD BACTERIOLOGY. 

The greatest argument in favor of boiling clothes 
in the laundry is based on the bacteriological reason. 
Body clothes, bedding, towels and handkerchiefs may 
all become soiled with discharges of the mucous mem¬ 
branes of the body or from some wound or pus 
formation. In most of these discharges there is sure 
to be bacteria. Soap has a slight disinfecting power, 
but the boiling is far more efficacious. Scalding or 
the pouring of boiling water over the clothes is not 
sufficient for disinfection, for only the top surface is 
subjected to the high degree of heat necessary to 
kill the germs. Soap or other alkali, boiling, fresh 
air, and sunshine are a sanitary quartet whose work 
results in sterilization—that is, in death tp the germs. 

The natural home of the bacteria is the soil. Here 
they are most numerous because here they have their 
greatest field of work laid out for them, which is to 
change any dead vegetable and animal matter that may 
be present into inorganic substances which can do no 
harm to life. 

When winds blow over the soil they raise the dry 
dust particles laden with bacteria into the air; rain 
washes millions of them from the air and soil into 
the brooks and rivers; therefore, all surface waters 
are seeded with bacteria. 

From the soil they may be directly brought into the 
house on shoes, or clothes, or hands; indirectly through 
dusty air. 

The cleaning of shoes on a mat, brush, or scraper 


BACTERIA. 


3i 


outside the front door is a habit to whicfi all chil¬ 
dren should be trained. Adults should think what it 
means to bring street filth into the dry, warm house. 
If all coats, dresses, etc., worn on the street could be 
brushed out of doors still another fruitful source of 
dangerous dust would be avoided. House air is 
found to contain thousands of bacteria, where out-of- 
door air may have only hundreds, because moist sur¬ 
faces catch and hold them. Sunlight and large 
amounts of fresh air tend to kill them. The house has 
less fresh air, less sunshine, and it is filled more or 
less with dry, rough furnishings, which add to the dust 
and all tend to hinder its removal and to lessen the 
chances of disinfection. 

In the laboratory bacteria are studied in many 
ways. Under the microscope is noted their shape and 
size; what kind, and the rapidity of motion, if any; 
how they tend to arrange themselves upon division; 
whether spores are formed or not. 

From plate and other cultures can be seen the 
shape and color of the colony; whether they grow 
best on the surface, in much air, or below the surface 
where air is excluded; whether the temperature of 
the room is more favorable than that of the incubator, 
which is much higher and represents more nearly 
the conditions inside of our bodies. 

Some of the bacteria secrete an acid which lique¬ 
fies the gelatine on which they may be growing. This 
acidity can be detected by litmus paper. Some pro¬ 
duce a gas when grown in a sugary solution, others 


Laboratory 

Study 


Secretions 


32 


HOUSEHOLD BACTERIOLOGY. 


Importance 

of 

Bacteriology 


cause putrefaction. Each of these differences means' 
much to the trained observer, for from such results 
has been and must be gathered our knowledge of 
their probable behavior outside of the laboratory. 

In the bacteriological laboratory has been found 
out facts which in the commercial life of the world 
mean millions of dollars; there, too, have been started 
experiments which have led to incalculable saving of 
human suffering and life, through sanitation, pre¬ 
ventive medicine, and surgery. 

Here we see how the little things of life have con¬ 
founded the mighty and how “the science of the 
infinitely small/’ by which some one has defined bac¬ 
teriology, “has become the infinitely important.” 


DUST PLANTS . 


33 


MOLDS 

Another micro-organism which is seldom absent 
from house dust, either as the plant cell itself or its 
spore, is mold. This in our dust garden formed the 
:olonies with dark centers and a velvety pile. Molds 



FIG. 18. A GROWTH OF MOLD. 

Mycelium, Hyphae and Spore-cases. (After Jorgensen.) 

consist of vegetative portions which grow out in long 
threads, and these by budding and branching unite 
to form a network over the substance they are using 
as food. Fig. 18. 

From this network or mycelium grow out cells called 
hyhae set apart for special wprk—that of bearing the 
reproductive portion—the heads or stalked clubs. 
Inside these heads or from their outer surface 


Growth of 
Mold 


Reproduction 







34 


HOUSEHOLD BACTERIOLOGY. 


4 



FIG. 10. MOLDS SHOWING A MYCELIUM BRANCH, (m.) 


(a) With ripe spores (s). 

(b) A spore-bearing stalk with spores just forming. 

(c) Spores have fallen. (After Jorgensen.) 

















35 


MOLDS. 

grow the spores which are to reproduce the species. 
Figs. 19 and 20. Each head produces thousands of 
dust-like spores. Fig. 21. This is the 
common method of. reproduction in the 
molds, although some, like the bacteria be¬ 
low them in the scale of nature, break the 
parent cell into segments, while others send 
off buds like yeast. These buds form di¬ 
rectly the second generation. 

When the invisible spore falls upon a 
moist, warm surface, it immediately begins 
to grow by sending out the mycelium 
branches, which will then proceed as before 
to develop more spore-bearing cells. 

Sometimes these mycelium cells pene¬ 
trate into the food substance, very much 
like the roots of the higher plants. 

One of the effects of mold growth is seen in the soft¬ 
ening of cellulose in fruits, vegetables, etc. This makes 
their decomposition by the bacteria more speedy and 
thorough. Out-of-doors this action is of great use in 
the economy of Nature, but inside our houses the pres¬ 
ence and growth of molds should be guarded against 
in every way. 

In general, molds will grow with less moisture than 
bacteria, and some of them flourish in the light. They 
increase rapidly after rainstorms and are much less 
affected than the bacteria by winds. They need or¬ 
ganized food, as we well know from the places where 
we find them growing—bread, meat, leather, sugary 
liquids, or even in vinegar. 



Mold 

Spores 



3<5 


HOUSEHOLD BACTERIOLOGY . 


WO Moid8 S enera l» ^ey form fewer desirable products 

than do the bacteria, although this may be consid¬ 
ered a matter of taste. Those who like Limburger 
and Brie cheese; the Chinese “soy,” which is made 
from a kind of bean on which mold has grown; the 
Japanese “sake” or rice wine, which has been fer¬ 
mented by molds—these persons certainly would 
claim that molds were as valuable in the production 





FIG. 21. DIFFERENT STAGES IN THE DEVELOPMENT OF MOLD. 

(a, b, c and d) Growth of the spore-eases. 

(d’) The spore-eases open. 

(e) Spores. (After Jorgensen.) 


of flavor as the bacteria are in butter and ordinary 
cheese. 

Just what their action is upon digestion is not defi¬ 
nitely understood. It is thought that many of them 
cause a lax condition in the bowels, possibly diar¬ 
rhoea. 

Disease They are found to cause various diseased condi- 

from Molds y 

tions of the skin— Ringworm, Thrush, and Moth. 
The moth patches, often called Liver spots, because 
believed to be due to an inactive liver, are found to be 
caused by mold spores which have gained access to 




“DUST GARDEN” SHOWING ABUNDANT GROWTH OF 

MOLDS 


Made by a Member of the A. S. H. E 












t 




















* 














r.. 


* 1 , • 


«• 

r 



















* 












































• ► 




















































MOLDS. 


37 


the body tissues through some break in the skin. 
Fairly strong acetic acid—40 per cent—is one of the 
best remedies for moth. 

They sometimes penetrate quite deeply into the tis¬ 
sues, causing irritation, inflammation, or sores very 
difficult to heal because there can be no healing until 
the plant is killed. 

Food fully penetrated by mold growth would bet¬ 
ter be destroyed. When the growth occurs only on 
the surface, as on jelly, olives, pickles, etc., the mat of 
cells protects the food beneath and most of it is un¬ 
harmed. Such foods, however, are often softened 
by the products of mold and bacterial growth, when 
no sign of mold appears on the fruit itself. If eaten, 
various intestinal disorders are liable to occur. 

Moist cloth furnishes favorable soil for mold when 
warm and not open to fresh air. The folded gar¬ 
ments laid away gather moisture; dust containing 
mold spores is usually present on them, and in time, 
soon or late, the garments grow musty even if there 
be no visible mold. Mustiness is the proof of mold, 
and mold the proof of dampness and dust. We call the 
mold growing on the cloth mildew, but called by either 
name it is the same dust-plant. The plant must be 
killed to stop its growth. If it has grown only on 
the surface of the fibre, the stain may sometimes be 
removed without serious injury. If it is of long 
growth or has penetrated the fibre, a hole will result, 
because of the weakened or actually destroyed fibre. 

So far as the healthful house is concerned, there 


Mildew 


38 


HOUSEHOLD BACTERIOLOGY. 


Moldy 

Houses 


need be no separation in the mind between molds and 
bacteria, because the occurrence and conditions of 
growth of both are practically alike. So far as is 
known, there are no molds that cause such serious and 
fatal diseases as some of those caused by bacteria. 

Because molds are lighter than the bacteria, it 
takes much longer for them to settle. The air, 
then, is likely to contain molds even where it has 
been quiet so long that the bacteria have all settled. 
This gives the housewife another reason for the 
economy of keeping the air of her kitchen, pantries, 
or any place where food is prepared or stored, as free 
from dust and as dry as possible. 

In old houses it is sometimes impossible to keep 
food in certain closets or cupboards. The woodwork 
or plaster and therefore the air is so charged with 
mold spores that one damp day or the presence of 
warm, moist food alone will cause them to spring 
into growth. Such places should be often white¬ 
washed and painted or disinfected. 

The spores of molds are often very beautiful in color 
when seen in mass, and under the microscope they 
show exquisite forms and delicate ornament. These 
factors, as well as the substances upon which the mold 
grows, are used as means of distinguishing species. 

The botany of molds is to many as interesting a 
study as that of the higher plants. Only a micro¬ 
scope can bring out the beauties of this class of dust- 
plants, which from the standpoint of economy and 
health the housewife can view with disfavor second 


YEASTS. 


39 


only to that she bears for some of the bacteria. So 
many more of the bacteria are friends rather than 
foes that it may be more just to place mold as her 
chief enemy. 


YEAST 

The third variety of plants found in dust is yeast. 
These are not usually so numerous as either the bac¬ 
teria or ^he molds, although about apple trees in the 
country wild yeasts are common. Like a bacterium, 
the yeast plant is a single microscopic cell of pro- 
tpplasm enclosed by the cell wall. It is round or oval 
in shape and often one two-thousandth of an inch in 
diameter. Fig. 22. It is therefore quite a giant com¬ 
pared with the smallest bacterium. 

If a drop of tepid water in which bread yeast has 
been dissolved be carefully watched under the micro¬ 
scope, the changes shown in Figs. 23 and 24 may be 
seen. One cell will be &een to swell a little at one 
part. This bud or daughter cell will bulge out more 
and more from the parent and may even produce one 
or more generations from itself before it breaks away. 
This ‘‘budding’' is the method of reproduction common 
to yeast plants of which there are many varieties. 

Some species, however, reproduce by spores very 
much like the molds. Such yeast cells will be seen 
to divide within the cell wall into two or four rounded 
bodies which in growing soon rupture the parent 
cell and escape. Fig. 25. Each of these liberated 
spores forms a new plant which may produce buds. 


Size and 
Structure 
of Yeast 


Spores 


40 


HOUSEHOLD BACTERIOLOGY. 


Requirements 
for Growth 


Products 
q( Growth 


Thus the generations are continued and the individuals 
multiplied. 

Yeast requires food, oxygen, warmth, and moisture. 
Sugary substances are especially liked by the yeast 
which is used to make bread. This is a specially cul¬ 
tivated form of brewer’s yeast. Yeast directly from 



FIG. 22. TYPICAL FORMS AND APPEARANCE OF BREWERS’ 
YEAST. (After Sedgwick and Wilson.) 

the breweries is often used for breadmaking. It 
is while feeding upon these sugary solutions that 
the tiny plants bring about the chemical changes by 
which alcohol and the gas, carbon dioxide, are pro¬ 
duced, The gas puffs Up the dough and makes pos^ 




YEASTS. 


4i 


sible the raised bread, or the “election cake’’ like that 
of our grandmother's time; it also produces the 
“froth” and “sparkle” of the “home-made spruce beer” 
as well as that of the large breweries. 

Yeast plants grow best from 70 0 F. to 90° F. They 



do not work well under 70 0 F. and are killed when in 
a moist state by the temperature of I30°-I50° F. No 
wonder the bread will not rise when the cook pours 
boiling or even hot water on the cake of yeast! Dead 
plants cannot; work any mQre than d^ad animals, Nq 


Favorable 

TsmperaturQ 




42 


HOUSEHOLD BACTERIOLOGY . 


Cold and 
Yeasts 


Experiment 
with Yeasts 


working by the yeast means no possible raising of the 
dough by the gas. Sometimes the dried yeast cake 
has been carelessly prepared in this respect and the 
yeast plants are nearly all dead. 

The yeast plants can endure cold better than heat. 



FIG. 24, YEAST PLANTS IN VARIOUS STAGES OF BUDDING OR 
REPRODUCTION. (After Sedgwick aud Wilson.) 


It hinders their work but does not quickly kill them. 

To show the favorable or unfavorable tempera¬ 
ture for the growth of yeast plants, take one-half 
cup each of boiling, lukewarm and ice-cold water. 
Add to each one tablespoonful of molasses and one- 




YEASTS . 


43 


sixteenth of a cake of compressed yeast. Put each 
portion into a clear glass bottle or tumbler and place 
all three in a warm place, about 75 0 or 8o° F., for an 
hour or two. Watch carefully for the first sign of 
bubbles which show that gas is forming. Note in 
which glass the larger amount of gas is found. 



FIG. 26. YEAST GENERATING CARBON DIOXIDE. 


(a) Tube filled with molasseg and water. 

(b) Carbon dioxide collecting In top of tube. 


Fill a test tube or thin, clear glass vial with a 
mixture of molasses and tepid water. Add a little 
yeast and invert the vial in a dish which also con¬ 
tains molasses and water. Fasten the vial so that it 
will remain standing, closed, in the dish for a day or 
more. Fig. 26 j a and. b % 




























44 


HOUSEHOLD BACTERIOLOGY. 


The Gas 
Produced 


Compressed 

Yeast 


The gas will be formed, replacing the water in the 
vial. If a burning match is held in the mouth of the 
tube as it is removed from the water, the flame will 
be extinguished. This indicates that the vial con¬ 
tains the gas carbon dioxide; or a teaspoonful of 
clear lime water may be poured into the vial and 
shaken about in it. The carbon dioxide present will 
turn the lime water milky from the insoluble car¬ 
bonate of lime (calcium) formed. 

Compressed yeast is sim¬ 
ply a. mass of yeast plants 
mixed with some form of 
starch and pressed into 
cakes. A two-cent cake is 
said to contain over half a 
billion yeast plants. 

As these cakes are made 
ior a special purpose they 
should contain only one species of yeast. They do, 
however, contain bacteria and if the dough is allowed 
to rise too long or at too high a temperature they 
grow and produce an acid which makes the bread 
sour; so that sour bread results from the growth of 
bacteria and not from the yeast. When pure yeast is 
used and all conditions of cleanliness are carefully 
looked after no sour bread results. A dusty kitchen 
or unclean utensils may increase the danger from bac¬ 
terial growth. If the bread be made with milk, this 
should be scalded to kill the bacteria always present. 
As we have seen, milk is rich in dust-plants, especially 



FIG. 25. A YEAST CELL CON¬ 
TAINING FOUR SPOItfcS. 



YEASTS. 


45 


bacteria, and the dirtier the barn, the cows, the pails, 
or the clothes and hands of the milker, the more bac¬ 
teria the milk contains. 

The baking of bread should kill both the bacteria 
and yeasts, as well as molds, if any are there. But 
it will not do this unless continued for a long time, 
because the inside of the loaf will not be raised to a 
temperature sufficiently high. The moisture in the in¬ 
terior prevents a temperature much higher than 212° 
and it may renlain far be¬ 
low this. 

In the laboratory bread 
has been made from the 
yeast plants found alive in 
the center of a slack-baked 
loaf. The bread should re¬ 
main in the oven until well 

Fig. 27. Bacteria Found in the 

done, then when removed “Eyes” of Potatoes, 

it should be cooled as rap¬ 
idly as possible, that all growth of yeast or'bacteria 
may be stopped. 

The custom of some housewives of wrapping the 
hot loaf in thick cloth that the steam may soften tjie 
crust is entirely wrong from a bacteriological stand¬ 
point. 

During the baking the alcohol and carbon dioxide 
are both driven off. 

Coarse breads, those containing much bran espe¬ 
cially, need thorough baking, because on the outside of 
the grains are often certain bacteria, the spores of 
which are very resistant to even high heat, 



Baking 

Bread 


Coarse 

Meals 





4 6 


HOUSEHOLD BACTERIOLOGY. 


Some of these are found in large numbers in the 
soil which clings to underground vegetables, especially 
in the “eyes” of potatoes. No wonder a vegetable 
brush is necessary to clean away these clinging arms! 
Fig. 27. 


TEST QUESTIONS 


The following questions constitute the “written reci¬ 
tation” which the regular members of the A. S. H. E. 
answer in writing and send in for the correction and 
comment of the instructor. They are intended to 
emphasize and fix in the memory the most important 
points in the lesson. 



HOUSEHOLD BACTERIOLOGY 


PART I. 


Read Carefully. Place your name and address on the first 
sheet of the test. Use a light grade of paper, write on one 
side of the sheet only, and leave space between answers. 
Use your own words, so that your instructor may know that 
you understand the subject. Read the lesson book a num¬ 
ber of times before attempting to answer the questions. 
Answer every question fully . 


1. What are bacteria? Describe them. 

2. What other microscopic forms are found in 

dust and what are favorable conditions for the 
growth of these dust-plants ? 

3. Where are bacteria most numerous and what is 

their chief work in the world ? 

4. In what ways are bacteria helpful to man and 

in what way do they injure him or his pos¬ 
sessions ? 

5. Why should food eaten raw or unskinned be 

thoroughly cleaned? 

6. What sanitary end is attained by cooking food ? 

7. Why are oranges and bananas safer fruits than 

grapes or peaches bought from a street ven¬ 
der? 

8. How can scalding apple or other sauce prevent 

its spoiling, and why scald it more than once? 




HOUSEHOLD BACTERIOLOGY. 

9. What common diseases in man are attributed to 
molds ? 

10. What is mildew, and under what conditions in • 

the house would it be likely to appear? 

11. Are molds ever helpful to man? 

12. From the health standpoint, what clothes are 

most likely to need boiling ? 

13. Why should milk receptacles be thoroughly 

scalded or sunned? 

14. When a can of blueberries ferments or “spoils,” 

what does it mean ? 

15. Why are bacteria considered to be plants? 

16. How do bacteria reproduce themselves and what 

food do they prefer? 

17. What is the typical mode of reproduction in 

yeast? In mold? 

18. What is the chief work of the yeast plant? 

19. Give a report of your dust-garden experiment. 

20. What do you consider the most important ways 

in which you have applied the knowledge 
gained from this lesson? 

21. Are there parts of this lesson that are not clear? 

Have you some questions? 

Note.—After completing the test sign your full name. 





HOUSEHOLD BACTERIOLOGY 


PART II 


■V 


4 •• 






V 



CELLS OF CLOVER TUBERCULE, SHOWING BACTERIA 
HIGHLY MAGNIFIED 





HOUSEHOLD BACTERIOLOGY 


PART II. 


WORK OF BACTERIA 

When bacterial life first appeared upon the earth 
may never be known, but that it existed thousands of 
years before man made its acquaintance is surely true. 
Indeed, it was within the last quarter of the nine¬ 
teenth century that the knowledge of bacteria became 
of value or was reduced to a science. The problems of 
bacteriology are now being solved very rapidly. What 
future generations may add, who can tell ? 

Although bacteriology is the youngest of all the 
sciences, it occupies a very important place among 
them because of its intimate connection with disease, 
with sanitation or the prevention of disease; with 
successful agriculture, and with the manufacture of 
many products. 

In the eyes of the law every person is considered 
innocent until proved guilty. It may be well for us 
to look at the beneficent role which bacteria play in 
the world, that we may the more justly consider 
their harmful work. We can hardly believe that the 
most numerous forms of life were intended to work 
only harm to man. 


Useful 

Bacteria 


47 



48 


HOUSEHOLD BACTERIOLOGY 


Bacteria as 
Scavengers 


As soon as an organism begins to live it begins to 
die; that is, certain cells or parts of cells die and are 
perhaps cast off from the rest that the whole may 
not be injured. Animals and 
plants die and become dan¬ 
gerous to the welfare of 
other animal life, especial¬ 
ly to man. The wastes of 
life, of his own life even, are 
man’s greatest menace. 

Here come to his aid these microscopic scavengers, 
the bacteria. No doubt the molds assist in the process 
but the balance of the work is done by the bacteria pres¬ 
ent in such infinite numbers everywhere on the earth 
where organic matter exists. 

Through their agency all 
dead animal and vegetable 
substances—that is, all or¬ 
ganic matter—are changed in¬ 
to inorganic matter, into the 
chemical compounds or ele¬ 
ments out of which they were 
originally constructed, and 
which are harmless or helpful 
to the life of the world. 

A tree falls in the woods; an elephant or a bird 
dies in the jungle; just then and there the millions of 
bacteria in the soil and the air are ready to seize upon 
the dead bodies, and in time all the animal and vege- 



Fig. 29. Bacteria Found in 
Soil and on the Roots of 
Clover, Peas and Other 
Leguminous Plants. 



Fig. 28. Bacteria in Soil 
which Help in Making 
Plant Food. 


WORK OF BACTERIA 


40 


tables tissues are changed into gases which dissipate in¬ 
to the air or reunite into 
compounds' that form a 
part of the soil. These 
then become once more 
food for plant life, and 
this, in turn, for the sus¬ 
tenance of animals. 

Bacteria are the agents 
of decay by which all or¬ 
ganic materials are re¬ 
turned to the soil or the 
air. Thereby life is not 
only made possible, but 
also is sustained. What 
the conditions would be 
were these invisible agents 
to cease their beneficent 
work of scavenging can be 
scarcely imagined. Life 
as we know it on this earth 
could not exist were these 
dust-plants not present. 

All animal life is de¬ 
pendent directly or indirectly upon the vegetable 
kingdom for sustenance. Man takes both animal and 
vegetable food, but he is not able to manufacture this 
food out of the inorganic elements. 

Plants use for their food gases, water, and various 
salts usually dissolved in the water. In sunlight the 



FIG. 30. A VARIETY OF PEA. 

(a) Grown in soil with the 

proper nitrifying bac¬ 
teria. 

(b) Grown under the same 

conditions without the 
bacteria. 


50 


HOUSEHOLD BACTERIOLOGY 


Nitrogen 
Not Taken 
Direct 


green leaves through their chlorophyl cells are able 
to take most of their carbon from the carbon dioxide 
of the air. Some oxygen is also taken from the air, 
but most of it is absorbed by the rootlets from the 
ground air, the water in the soil, or from organic com¬ 
pounds in solution in the water. Hydrogen is ob¬ 
tained from water and other compounds containing 
hydrogen and is taken in through the rootlets. 

No plants can take their nitrogen directly from the 
air. Although this gas with oxygen comprises the 
major part of the atmosphere in which all vegetation 
is bathed, it is not taken in through the leaves as the 
carbon dioxide is. 

A government bulletin says: “Ever since anything 
has been known in regard to plant nutrition and the 
necessary part that various gases and minerals play 
in the successful growing of crops, scientific men have 
realized the great importance of conserving the world's 
store of nitrogen and have made every effort either to 
husband or to increase all available sources of supply. 
In the early days, when it was first realized that 
nitrogen was so essential to plant life—in fact, was at 
the very foundation of agriculture—no particular 
alarm was felt. Botanists had demonstrated that plants 
obtained their carbon from the carbon dioxide of the 
air, and since this gas is present in so much less quan¬ 
tity than nitrogen it was believed that by no possible 
means could the most essential of plant foods be ex¬ 
hausted. However, when it was shown that plants 





Hoots of nrimson clovor showing nodules Roots of sweet pea showing nodules. 








































- 























































\ 





























/ 




















































♦ 





















































V * 





















* 































































WORK OF BACTERIA 


5i 


were unable to use free atmospheric nitrogen and 
must obtain it directly from the soil in a highly or¬ 
ganized form, the importance of the problem increased 
greatly, and the gravest consequences were predicted 
by those familiar with the rapidity with which this 
valuable element was being wasted.”—Farmers’ Bulle¬ 
tin No. 214, Beneficial Bacteria for Leguminous 
Crops. 

Nitrogen in combination available for plant food is 
wasted in many ways. Food and other organic wastes, 
as sewage, are burned or run into the sea instead of 
being returned to the earth, which is the natural place 
of disposal. 

There are natural sources of stored nitrogen in 
saltpeter beds and guano deposits, but these are rapidly 
disappearing. Even if they were sufficient in quantity 
they are not everywhere present and therefore must 
be expensive. Their aid would not be available for all. 

The bacteria are more generally present and ready 
to work. Although unknown and therefore uncred¬ 
ited, they have been working during all the ages since 
vegetation appeared, not only by their general agency 
in producing fertility of the soil through the products 
of decomposition, but also in certain plants through 
their ability to take from the air its free nitrogen. 

From the earliest days of agriculture it has been 
recognized that all plants belonging to the leguminosae 
have a decidedly beneficial effect upon the soil. Pliny 
wrote: “The bean ranks first among the legumes. 


fraste of 
iTitrogen 


Nitrifying 

Bacteria 


52 


HOUSEHOLD BACTERIOLOGY 


Nitrogen 

Traps 


Enrich 
the Soil 


Inoculating 
the Soil 


It fertilizes # the ground in which it has been sown as 
well as any manure.” The lupine and vetch are also 
mentioned in ancient writings as enriching the soil and 
supplying the place of fertilizers. 

On the roots of these leguminous plants, clovers, 
alfalfas, peas, beans, etc., are seen little nodules which 
have been found to be filled with bacteria. Fig. 29. 
If these “nitrogen traps” are absent or are removed 
the plants are less vigorous. Fig. 30 shows the com¬ 
parative size of two plants of a variety of pea; (a) 
grown on soil containing the proper kind of bacteria; 
(b) grown in the same conditions and soil, but with¬ 
out the bacteria. The nitrogen is stored up in the 
knots, swellings, or nodules on the roots. 

Not only do these nitrifying bacteria thus feed the 
plants which carry them, but also when the plants de¬ 
cay they enrich the soil in which the plants grow. Soils 
“run out,” as the farmers say, that is, there is not plant 
food enough to sustain luxuriant vegetable life. Here 
is a place for the legumes to supply with their tiny 
balls of bacteria the nitrogen which has been with¬ 
drawn. In some way, not understood, the clover or 
similar plant in company with the bacteria stores up 
nitrogen from the air, which is finally returned to the 
soil when the decomposition bacteria have accom¬ 
plished their work, thus making the soil richer in 
nitrogen. 

When the proper kind of nitrifying bacteria are not 
present, the scientist comes to the aid of the farmer 


WORK OF BACTERIA 


53 


and supplies him with artificially grown bacteria with 
which he may inoculate the soil or seed. If the soil 
is favorable otherwise, the crop is greatly increased 
and in time the soil made more profitable for other 
crops. 

The wise farmer does not plant potatoes or corn 
in the same piece of ground two years in succession, 
unless he adds large quantities of fertilizer or plant 
food. He rotates his crops because different species 
of plants take from the soil different kinds or amounts 
of food. 

Even if these two fields of work—scavenging and 
aid in agriculture—were all in which we make use of 
bacteria, their claim of helpfulness would be over¬ 
whelmingly proved; but other results of decomposition 
processes are valuable in the arts and in the commerce 
of the world. 

By the action of bacteria upon the whitish juice of 
certain plants fermentation processes are set up which 
result in the blue indigo so important in dyeing indus¬ 
tries. Our grandmothers would have been surprised 
indeed had they understood that their solid bluing was 
once a white liquid. 

Bacteria, too, make possible the retting of the flax, 
whereby the fibres are separated from the stalk to be 
finally woven into the beautiful “pictures in white” 
we call table damask. 

They bear their part in the preparation of sponges 
and in many processes of tanning and tobacco curing. 


Rotation 
of Crops 


Fermentation 

Processes 


54 


HOUSEHOLD BACTERIOLOGY 


Flavor 

Production 


In these “maceration industries” advantage is taken 
of Nature’s methods of decomposition and what she 
did for countless ages before man studied her “ways 
and means” he still lets her do for his own and the 
world’s commercial benefit. Her bacterial agents are 
as ready to work on the large 
scale of his planning as on 
the small scale of the stems 
of mignonette left too long 
without fresh water in a vase 
on our tables. 

Yet these are not all. Not 
only do they act directly and 
Fig. 31. a Bacterium which indirectly in furnishing food 

Makes Milk Sour. 1 & 

to plants, which afterward 
become food or fuel to ani¬ 
mals and man, and prove a source of wealth to man 
in his industries, but they also greatly increase the 
variety and the palatability of his food. 

Milk as we know it always contains bacteria and 
is an excellent culture material for their growth. Such 
a universal condition suggests some important results 
to be attained. 

Most housewives know that while cream may be 
sour it is not so sharply acid as the milk from which it 
was taken. The addition of a little salt or sugar and 
spices may counteract this acidity and the result be 
a most delicious sauce. The large amount of fat in 



BUTTER MAKING 


55 

the cream is not a favorable food for the lactic acid 
bacteria. Fig. 31. 


BUTTER MAKING 

Butter is usually made from sour or “ripened” 
cream and this ripening is the work of bacteria. The 
bacteria which cause the ripening are of different 
species, which grow best at different times and under 
different conditions. As the re¬ 
sult of their growth are pro¬ 
duced many different odors or 
flavors in the cream and the 
butter. Those that make the 
most desirable flavor, aroma or 
taste flourish best in May or 
June in this part of our country. 

Therefore, butter made from 
cream ripened by these bacteria has the qualities which 
have made “June butter” a synonym for the best. 
Figs. 32 and 33. 

Conditions over which the housewife has little con¬ 
trol may interfere with the products. If the weather 
be warm and moist, the cream and butter need dif¬ 
ferent care than when the temperature is low, the air 
dry or the climate equable. She therefore tries to 
produce an artificial climate by putting her cream and 
churn in a cold room and the butter in the refrig¬ 
erator. 



Fig. 32. A Bacterium 
Which Gives a Pleas¬ 
ant Odor to But¬ 
ter. (After 
Conn.) 


Butter 

Bacteria 


5<5 


HOUSEHOLD BACTERIOLOGY 


June Flavor 
Bacterium 


This flavor production is a true process of fermen¬ 
tation or decomposition and likd any other must be 
stopped at just the right time or results most undesir¬ 
able will be obtained. 

The skilled butter maker knows how careful she 
must be with dairy floor and shelves, milk pans, skim¬ 
mer and churn as well as with the milk, the time of 
skimming, the temperature 
and age of the cream, etc. 
From milk kept in some 
dairies it is impossible to 
make good butter — the 
wrong kind of bacteria are 
there. This is usually the 
result of uncleanness 
somewhere, it may be out¬ 
side the dairy or it may be 
within. 

This natural process of 
cream ripening may do for the small home dairy where 
all milk and its care can be under constant supervision; 
but in the public creamery, which receives milk from 
many breeds of cows under varying conditions, such 
chance ripening would lead to failures and much 
financial loss. 

When a pink or a rose is found to have a peculiar 
fragrance, color, or shape, or to keep longer than 
others, and this is perpetuated by cultivation, why not 
a certain “J une flavor” bacterium? This is just what 
is done. Fig. 34. 



Fig. S3. A Bacterium Which 
Makes Good Tasting But¬ 
ter. 


BUTTER MAKING 


57 


The first experiment in the culture of “butter 
bacilli was made from a specimen of milk which came 
from South Africa and was exhibited at the World’s 
Fair in Gnicago in 1893. 

This was named from the scientist who introduced 
the culture, “Conn’s Bacillus No. 41.” 

Now there are other varie¬ 
ties which are cultivated for 
the purpose. 

The butter of different 
countries varies much like 
that of different dairies in the 
•same country. Now, anv de¬ 
sired flavor may be obtained 
if a pure culture of the proper 
bacterium is used and the 
conditions of manufacture are 
understood and carried out. 

The culture introduced into 
the cream is known in the 
United States as a “starter.” 

There are different meth¬ 
ods of using the starter, but one in common use may 
be outlined thus: “The pure culture is added to a 
small portion of Pasteurized milk and allowed to 
grow. At the right time and temperature a certain 
amount of this ‘starter’ is added to the Pasteurized 
cream.” All the factors of success are kept under 
control; nothing is left to chance. The extreme meas- ? 



Fig. 34. A Bacterium Which 
Is Cultivated and Sold 
to Butter Makers. 
(After Conn.) 


“Starters” 



58 


HOUSEHOLD BACTERIOLOGY 


Bad 

Flavor 


Ripening 

Cheese 


nres taken to insure cleanliness are a revelation even 
to the neatest housewife. 

Not all bad flavors in butter are due to the wrong 
bacteria or to molds. The food and physical condition 
of the cow may affect the flavor of the milk and there¬ 
fore of the butter, but certain distinctive tastes or 
appearances, as an oily or soapy taste, bitter or ropy 
milk, red, blue and other colors in milk, which were 
formerly attributed to diet or 
disease in the cow are now be¬ 
lieved to be the work of various 
micro-organisms. Fig. 35. 

These are diseases in the milk 
as much as the fermentations in 
our bodies brought about by 
germs of consumption or diph¬ 
theria are diseases. Both are 
the work of germs which have gained access through, 
or are working under wrong conditions. 

Health in the human body as well as health in food 
supplies means conditions unfavorable for the growth 
of any germs or those conditions favorable only for 
the growth of helpful forms. For this end the bac¬ 
teriologist is always working. 



Fig. 35. A Bacterium 
Which Makes Milk 
Red. 


CHEESE 


Cheese is made from the casein of the milk and is 
a most valuable proteid food. However, it is seldom 


CHEESE 


59 


used as food until a ripening process has been carried 
on which gives it the most desired flavor and increases 
the digestibility of the albuninous matter by making 
it easier of solution. The change of the liquid milk 
into the solid curd is a chemical change, but to nu¬ 
merous species of bacteria and molds we are indebted 
for the many varied flavors which tickle the nerves of 
taste. 



Certain species grow best 
in damp, dark caves, and 
some of the foreign, strong, 
highly-flavored cheeses are 
ripened in these caves. 

Some species produce 
large quantities of gas which 
puffs up the cheese or leaves 
holes, large or small, few or 
many, according to the num¬ 
ber of bacteria present. Fig. 

Fig. 36. 

In some kinds of cheese, large holes are made in 
the finished product and mold spores inserted. These 
grow and give the characteristic flavor to the food. 
This is seen in the “Roquefort” which was first made 
in a French village of that name from sheep’s milk. 
Brie, Stilton, and Gorgonzola are also allowed to gain 
flavor from molds, while the Edam is inoculated with 
a bacterium. Sometimes the fermentations develop 
poisonous products of putrefaction which may result 


36. A Bacterium Which 
Makes “Swelled” Cheese. 


Molds in 
Ripening 
Cheese 



6o 


HOUSEHOLD BACTERIOLOGY 


Bacteria 
Necessary 
for Flavor 


in ptomaine poisoning. This would be putrid cheese. 

As with cream, so the cheese curd may be inoculated 
with the particular germ which, by its growth and life 
processes, is known to give the desired flavor, just as 
a person may be inoculated with a certain disease germ. 
In both the processes are similar, although the results 
are different. 

If cheese be made from boiled or Pasteurized milk 
or from that to which a germicide has been added, the 
ripening process does not go on, showing that the 
living micro-organism is necessary to the production 
of the desired flavors. 

Pure cultures are now used for cheese ripening and 
therefore cheeses that have heretofore been imported, 
because the species of bacterium necessary was not 
native to this country, may now be made here when the 
conditions of growth are understood. 

Butter and cheese are possibly the most common 
foods whose desirable and varied flavors are due to 
bacteria and molds, but there are others where their 
work is often productive of a pleasant taste. 

VINEGAR 

Anyone who has seen a cider mill in operation in 
the country or has seen the cider made “while you 
wait” at a city fair knows the process by which the 
whole apple is crushed and the juice extracted. Such 
juice must, of course, be seeded with wild yeasts and 
with bacteria which were on the skin of the fruit or 
in the air. When it runs directly from the press, it 


VINEGAR 


6i 


is only very slightly acid, but if allowed to stand for 
a while it becomes sharply acid. This acetic acid 
is the result of bacterial growth and finally turns the 
sweet, pleasant drink into hard cider or cider vinegar. 
Fig- 37- 

The process of change is a complex one, due to 
both chemical and bacteriological agencies. When the 


££ 3 > 









O 

0 

* w 

* 1 \ * * 

FIG. 37. BACTERIA WHICH MAKE ACETIC ACID AND VINEGAR. 
(After Conn.) 




wild yeasts have brought about the alcoholic fermenta¬ 
tion of the sweet apple juice certain bacteria take up 
the work and produce acetic acid in a weak solution 
which we know as vinegar. There are different spe¬ 
cies capable of producing acetic acid of different 
strengths and under different conditions. What is 
known as the mother-of-vinegar is a dense mass of 
bacteria—a true zoogloea form. Fig. 38. 


Sugar to 
Acetic Acid 



62 


HOUSEHOLD BACTERIOLOGY 


These are the agents which make the vinegar. 

Not all vinegar used in the household is made from 
cider. The large manufactories usually use alcohol 
or wine as the base of the process. Alcohol and acetic 
acid contain the same elements in different porportions, 
the former having less oxygen. The bacteria of 
mother-of-vinegar are able to take oxygen from the 
air, cause it to unite with the alcohol, and thus make 
acetic acid. In actual practice a weak alcoholic solu¬ 


tion is allowed to trickle 
lowly over beechwood shav- 
lgs. In this way a large sur- 
ice is exposed to the air. It 
found that if the shavings 
‘e sterilized, that is, if all 
icro-organisms are removed, 
o acetic acid is formed, thus 
proving that here again we 
are indebted to our dust-plant 
friends. 



FIG. 38. Bacteria in 
“Mother-of-Vinegar.” 


Butyric Lactic acid, the acid of sour milk, and acetic acid, 
Acid the acid of vinegar, are two desirable acids due to 
bacterial growth, while a third, butyric acid, not desir¬ 
able to the housewife, results when such growth takes 
place in fats. This is the chief cause of rancidity in 
butter and other oily substances and the similar taste 
or smell in old milk. To the housewife this means 
loss of food supplies and therefore comes under the 
unfriendly work of dust-plants. 



HARMFUL DUST-PLANTS 

The harmful work of bacteria and molds so far is 
seen to consist of two kinds, the production of unfavor¬ 
able conditions in food supplies, and in or on other 
property, as mildew on clothes, books or furnishings; 
in short, diseased conditions of our possessions. These 
diseases, if not cured, may be serious enough to destroy 
the property, while they may also cause similar diseased 
conditions in our own bodies, more or less severe, 
which may result in death. 

Bacteria sour our milk, our sauces, our fruit juices; 
they not only “ret” the flax when we wish them 
to, but they rot wood when we do not want them to; 
they make meat putrid and butter rancid; molds 
spoil our bread and jellies and clothes. All these things 
the dust-plants will do unless we prevent them, be¬ 
cause they are in the world to soften, to decompose, 
and thus to “get rid of what has ceased to live.” All 
such substances are food for them and feeding is their 
way of working. 

We must know how to prevent their work when it 
interferes with our interests. We must prevent their 
growth by removing conditions which are favorable or 
we must kill them. 

An experiment which anyone can try will suggest 
what favorable or unfavorable conditions are and in 
what way science seeks to help the housewife to pre¬ 
serve both her property and her health. 

63 


\ 


Life Work 
of Dust 
Plants 


64 


HOUSEHOLD BACTERIOLOGY 


■Experiments 

with 

Bacteria 


Experiment III. Take seven clear glass bottles, 
number or mark each in some way. (Small laboratory 
flasks with flat bottoms are convenient for this pur¬ 
pose.) Put into each one-half cup or less of milk or 
grape juice. 

Leave No. i open in a warm room, not in direct 
sunshine. 

Fit No. 2 with a full plug of cotton wool about one 
inch long. Put with No. i. 

Have No. 3 like No. i, but place immediately in an 
ice box. 

Drop into No. 4 one tablet or “saloid” of corrosive 
sublimate. This can be bought of a druggist. Mark 
it “Poison.” Plug like No. 2 and place it with No. 1. 

Plug No. 5 with cotton wool like No. 2. Put it into 
a steamer and steam for thirty minutes three days in 
succession. Place it with No. 1. 

Fit No. 6 with a tight cork. Remove the cork, but 
place it with the bottle in the steamer and steam as 
you did No. 5. Cork each bottle while the steam is 
coming out. As the cork cools and shrinks, tighten it. 

Put a cotton wool plug into No. 7 and heat for half 
an hour from 155 0 F to 165° F. 

After completed preparation, keep all but No. 3 
under the same conditions and note any changes that 
occur. Test the open bottles with strips of blue litmus 
paper from the druggist’s. See if the contents change 
the paper any more rapidly or completely after two or 
three days than at first, Test by smell and taste all 


HARMFUL BACTERIA 


65 


but No. 4, the one in which was put the corrosive 
sublimate. This is a poison to human beings when 
taken internally. 

No. 1 is open to air and dust and in time will be¬ 
come sour or undergo fermentation. If left long 
enough the milk may putrify. 

No 2 is closed to dust but not to air. However, 
no pains was taken to free the bottle or plug from the 
dust which was on them or in the contents, so in time 
this will become sour. 

No. 3 has all the conditions of No. 1 except warmth, 
which is favorable, and light, which to some dust 
plants is unfavorable. It should not spoil or sour as 
quickly as No. 1. 

No. 4 has been treated by a chemical which is poi¬ 
sonous and should kill the dust-plants present. This, 
if strong enough to kill, is a disinfectant. If only 
strong enough to prevent or retard growth for a while 
it would be an antiseptic. There should be no change 
in No. 4. 

No. 5 will have been sterilized, that is, all life within 
liquid, or bottle, killed by the steaming process. 
The first steaming is expected to kill all the growing 
or vegetative forms then present. It may not be enough 
to kill any spores' that are there. These will be en¬ 
couraged to grow by the greater heat, but on the sec¬ 
ond day they will have developed into 'the ordinary 
growing form and the steaming should kill them. 
That sterilization may be assured and any possibly 


Intermittent 

Sterilization 


pasteuriza¬ 

tion 


66 HOUSEHOLD BACTERIOLOGY 

resisting microbe destroyed, a third steaming is given. 
This is called intermittent sterilization. No. 5 should 
keep indefinitely. It will, of course, dry away slowly 
through evaporation. 

No. 6 is like No. 5, only closed from the air which 
passes through the cotton wool, and if the cork was 
sterilized it is impervious to dust. Some corks are not 
solid enough to keep the bacteria from growing 
through the cavities. Such corks need to be dipped 
in melted paraffin. They are then as tight as a glass 
stopper. No. 6 should keep, as well as No. 5. 

The woman who put up her grape juice in corked 
bottles, to find some years after that she had grape 
wine, either did not thoroughly sterilize the juice, the 
bottles and the corks, or the latter allowed dust to pass 
or mold to grow through. She should have covered 
the corks with melted paraffin to prevent such a pos¬ 
sibility. 

No. 7 varies from No. 5 only in the time and the 
degree of heat to which it was subjected. In the case 
of milk—where the process is most commonly used— 
this is called Pasteurization. It is sufficient to kill 
most if not all the souring bacteria and all the disease- 
producing or pathogenic germs. It does not affect as 
unfavorably the digestibility of the milk as steriliza¬ 
tion, 212 0 F, or higher is found to do. 

Pasteurized milk will spoil eventually because not 
all the germs are killed. Pasteurization is valuable for 
protection from disease germs and to improve the keep- 


PRESERVING FOOD 


67 


ing qualities of milk or cream. As it is not a process 
of sterilization, such milk, sometimes grows putrid or 
bitter without souring. 


FIG. 39. Diagram Showing Effect of Pasteurization Upon Milk. 

Fig. 39 represents the change which takes place in 
the germ content of milk during this process. If we 
represent the germ content of a sample of raw milk 
by the size of the white square, then the black square 
will show the same after Pasteurization. 

All additions of bacterial poisons are liable to injure 




68 


HOUSEHOLD BACTERIOLOGY 


Common 

Methods 


the persons using the milk ; therefore, in most cases, 
such additions are contrary to law. 

PRESERVING FOOD 

The following from the U. S. government bulletin 
on ‘The Use and Abuse of Food Preservatives/’ will 
show us that man has always sought to prevent x the 
use of his food by these micro-organisms: 

“In hot, arid regions the question of the preservation 
of food is of little interest. An animal may be slain 
and its carcass hung in the air to dry. Other foods 
keep correspondingly well. Putrefaction and decay 
are almost unknown. On the other hand, wherever 
climatic conditions favor decay this question becomes 
important, especially for those who live at a distance 
from markets and who kill and preserve their own 
meat, and for those who, either on land or sea, are 
for a number of days remote from a source of supply. 

“The methods most commonly employed for pre¬ 
serving food, by drying and smoking and with salt, 
vinegar, alcohol, and sugar, have long been known. 
Some of them are probably as old as civilization itself, 
and indeed are not unknown to many tribes of savages. 
We are told by Herodotus that the ancient Egyptians 
were conversant with the art of preserving meat with 
salt, and six centuries before the Christian era Cyrus 
sustained his troops on long expeditions with salted 
meat. The aborigines of North and South America 
were accustomed to cure their meat by smoking or 
“jerking” (tearing from the bone in long strips and 


PRESERVING FOOD 


69 


drying in the sun)* according to the requirements of 
the climate. The preservation of meat by salting, dry¬ 
ing, and smoking is practiced in Oriental countries by 
a number of the Mongolian tribes, including the Tar¬ 
tars and the Chinese. 

“It is a matter of common information that these 
methods are still employed largely in civilized coun¬ 
tries and not alone by those in rural districts who 
preserve their own meat. Our large packing houses 
smoke immense quantities of meat with hickory wood. 
One establishment in Chicago has 43 smokehouses, 
each of which holds 60,000 pounds of ham or shoulder 
or 120,000 pounds of side meat, besides n houses of 
half that capacity. Meat so preserved is recognized 
as wholesome. It is not always suitable for the sick 
room, but its taste is a sure indication of its character 
and the method of its preparation. This makes it im¬ 
possible to mistake these products for fresh meat, and 
thus removes the great temptation to fraudulent prac¬ 
tice that attends the use of tasteless preservatives. The 
preservation of meat by freezing has always been 
practiced, and in localities where the temperature fa¬ 
vors this method nothing else is to be desired. Until 
recently, however, this method has necessarily been of 
limited application. * * * 

“No tasteless food preservative has been suggested 
which is entirely nontoxic, and which does not have a 
marked influence on digestion, even when taken in 
relatively small doses, Some there may be whose anti- 


No 

Tasteless 

Harmless 

Preservative 


Sugar 


Drying 


Canned 

Goods 


70 HOUSEHOLD BACTERIOLOGY 

septic action is so slight that food treated with the 
minimum amount necessary for its preservation is not 
unwholesome for adults in normal health. But in any 
case food so treated should be plainly labeled with the 
name and amount of the added preservative.” 

Condensed milk keeps because most of the water 
has been taken out and a large percentage of sugar 
added. This results in a thick, pasty mass, enclosing 
very little air, in which the few germs which survive 
the heating that the milk undergoes cannot grow and 
work. Decomposition is thus retarded or prevented so 
long as the milk is not exposed to any fresh deposit of 
dust. The contents of an open can will soon show 
mold or give other evidence of spoiling and when di¬ 
luted to the consistency of ordinary milk will sour like 
fresh milk. 

Fifty years ago the country housewives dried their 
own apples, plums, raspberries and blueberries for 
winter use. This drying of uncooked fruits is simply 
an antiseptic measure and they must be kept dry or 
they will spoil. They must also be carefully cleaned 
before use. Some of the germs are killed by the dry¬ 
ing process, but others enter the spore stage and are 
ready fdr work when moisture is furnished. 

The present-day housekeeper owes much of the vari¬ 
ety in her food supply to the possible preservation of 
fruits and vegetables through sterilization. “Canned 
goods” are sterilized by means of steam or boiling. 
The same process, of course, cooks the food, thereby 


PRESERVING FOOD 


7i 


killing any bacteria or other germs which might be 
in the vegetable or animal tissues. The cans are sealed 
while hot. 

In the household similar processes are carried on. 
To insure success, everything which touches the food 
should be sterilized—the jar and its cover, spoons, 
ladles or funnel. Hands and towels should not touch 
the edges of the mouth of the jar nor the inside of the 
cover, for they may carry dust enough to reinfect the 
fruit. 

When the canned food ferments or spoils it means 
that in some way it was not thoroughly sterilized or 
that dust-plants gained access to it afterward. Wherq 
sugar is used it should, of course, be put in before the 
sterilization, not afterward, unless it is made into a 
syrup and sterilized by boiling. If the housewife re¬ 
members that everything is dusty; that dust means 
dust-plants; that dust-plants mean the germs of fer¬ 
mentation and putrefaction, or “spoiling;” that noth¬ 
ing short of sterilization will insure indefinite “keep¬ 
ing,” she will know with what she is dealing and may 
act intelligently. 

If all dust could be removed from the air, the latter 
might have free access to her cans and no souring 
would follow. They might dry up, but they would not 
“spoil.” If the jar of food be completely sterilized, 
it can be stored anywhere in light or dark, warm or 
cold places; no fermentation occurs. But the chances 
of partial sterilization—a misnomer, of course, for such 


“Spoiling” 


Acids as 
Preservatives 


Essential 

Oils 


Salt 


72 HOUSEHOLD BACTERIOLOGY 

a condition is not one of sterility—are so many that 
the cold place adds the antiseptic “ounce of preven¬ 
tion.” So far as the bacteria are concerned, in the 
sunshine would be the best place to keep such stores. 
This, however, would in time fade the food and under 
some conditions would help to dry it, or crystallize the 
sugar. Here, as elsewhere, there must often be a 
choice among unfavorable conditions. 

Some food supplies, like rhubarb, are so strongly 
acid that bacteria will not grow in them. This is some¬ 
times canned in cold water with no cooking. Toma¬ 
toes and cranberries are sometimes canned in this way. 

Bacteria do not like strong acids, so the housewife 
saves her cucumbers, tomatoes, etc., by making them 
into pickles. These, however, will mold. 

The essential oils, as clove, cinnamon, mustard, etc., 
are antiseptic in their effects. They possibly lend their 
aid in the preservation of the fruit as well as in adding 
flavor. Mustard, especially, has strong disinfecting 
properties. Perhaps this is its greatest value as a con¬ 
diment, for it may act upon the bacteria liable to cause 
fermentation in the digestive tract. 

Strong solutions of salt prevent the growth of bac¬ 
teria. Common salt, both in brine and as powder, 
is perhaps the oldest preservative, and although it 
makes most food stuffs less digestible it is probably 
the least harmful of any antiseptic substances. This 
cannot be said of borax, boracic acid, salicylic acid, 
the sulphites and formaldehyde (formalin) ; all of 


PRESERVING FOOD 


73 


which when strong enough to hinder the growth of 
bacteria are thought to interfere more or less with the 
digestive processes of man. The use of any such sub¬ 
stance is prohibited by the U. S. pure food law. 

It would seem that eggs at least should be free from 
bacteria because of their enclosing shells. But experi¬ 
ments have shown that the newly-laid egg is sometimes 
infested with bacteria and their growth may bring 
about the decomposition of the egg. 

The more common danger, however, is that of un¬ 
clean conditions of nest or storage. The shell is porous 
to air and also, it has been found, to certain bacteria. 
The shells, then, should be clean. Eggs are often pre¬ 
served by a coating of shellac or in lime water. These 
methods exclude air, without which any germ inside 
cannot grow, and they prevent any germ on the out¬ 
side from passing through the shell. 

We see, then, why eggs should be kept in a clean, 
cool place, and if packed, the packing boxes or material 
should be clean. Eggs are often tainted by moldy 
packing boxes, sour hay, or dirty straw. 

Some of the less common acts of bacteria are inter¬ 
esting even if we suffer by them. 

Fig. 49 shows a plate which was placed on the out¬ 
side sill of a second-story window on the back of a city 
house. This window overlooked an open field border¬ 
ing on a large body of water. It was not, therefore, 
an especially dusty position and the day was quiet, with 
little wind. The fact that so many dust-plants were 


Clean 

Eggs 


Dust Garden 
Planted 
Out of Doors 


74 


HOUSEHOLD BACTERIOLOGY 


Liquuefying 

Bacteria 


caught in the twenty minutes’ exposure shows the con¬ 
dition in which uncovered jellies, puddings, sauces, 
etc., are likely to be when placed in such places to cool; 
therefore, it is not surprising that lemon jelly, jellied 
meat, etc., are sometimes found in a liquid condition in 
such a place. 

As we have said, some of the bacteria are capable 
of liquefying gelatine. If the right species of bacteria 
had happened to be present in the dust which settled 
in this place, nothing could have prevented the gelatine 
being liquefied, because the presence of the liquefying 
bacterium would have been unknown until its work 
had been done. A slight liquefaction is shown at the 
largest spot in Fig. 46. 

The teacher who followed a lesson on the dangers 
of dust by one on lemon jelly which she placed uncov¬ 
ered in the open window to cool, did not apply the 
scientific knowledge which she had. If she had done 
as well as she knew, the contents of her mold would 
have remained jelly and not become lemonade. 


DISEASE GERMS 

We have seen that these dust-plants may spoil our 
property and thereby cause us much expense. Did 
they do nothing else, we might not spend so much time 
or labor in studying them and their work. 

Just as among the hundreds of beautiful flowers in 

poison dogwoodor 

i 

n 

i 


b 
a 

FIG. 40. THE BACILLUS OF TUBERCULOSIS. 

(a) Taken from lung tissue, (b) As sometimes found in the sputum. 

among the luscious mushrooms a deadly “Amanita 
or as in a great city among the thousands of honest, 
harmless, law-abiding citizens there is an occasional 
thief or murderer; so among the millions of helpful 
bacteria there are a few which in man and animals 
cause disease of greater or less virulence. 

These are called infectious or contagious diseases. 
They are carried either by actual contact with dis- 



the woods and fields there is a 



Communicable 

Diseases 


75 





HOUSEHOLD BACTERIOLOGY 


No Germs 
l,'o Disease 


Favorable 

Conditions 


76 

eased tissues; by inhaled dust, as most often in tuber¬ 
culosis or consumption; or by food or drink in which 
was the germ which is capable of causing a specific 
disease—as typhoid fever, diphtheria, etc, or through 
some wound in the skin. bigs. 4°> 4B 4 2 * 

If the specific germ of typhoid fever, tuberculosis 
or pneumonia, etc., is not pres¬ 
ent the disease will not appear, 
no matter how “run down” or 
“below par” the person may be. 
But any condition short of nor¬ 
mal health—any weakening of 
the body by cold, indigestion, 
fatigue, overheating, lack of 
nourishment, etc., tends to lessen 
the resistance in some part or 
the whole of the body and makes 
the attack of any germ which 
comes along more surely suc¬ 
cessful. 

Any inherited weakness, as 
weak lungs, sluggish circulation, 
imperfect digestive powers, in¬ 
creases the danger or liability to 
attacks of germ diseases. Given the germ under fa¬ 
vorable conditions for its growth, it is then a question 
of the resistant power of the individual, aided, per¬ 
haps, by medical science, whether the body or the dis¬ 
ease will gain the victory. 



FIG. 


41 

Diphtheria. 
(After Conn.) 


Bacillus of 


DISEASE GERMS 


77 


It is believed by some scientists that the commonly 
prevalent species of bacteria, harmless under ordinary 
conditions, may change their character when settled 
in thickly crowded centers of population where dark¬ 
ness, dampness, bad air, insufficient or poor food make 
filthy habits of life. If these then gain access to human 
tissues they may develop disease-producing power and 
be carried far and wide. In this- way cholera, the 
“plague,” and similar diseases, beginning in countries 
or sections of cities where human beings herd together 
with no pretense of cleanliness, are carried across seas 
and continents. This would show how necessary to 
the physical health of the 
world is the purification of 
“the slums,” whether these 
occur at home or abroad. 

Other bacteriologists denv 

... . . ' FIG. 42. Typhoid Bacillus Show- 

this hypothesis, but how- ing the Many Cilia. 

... (After Sedgwick and Wilson.) 

ever the disease germs may 

have developed their evil ways, they never, so far as 
we know, reform of their own accord and become 
harmless, although unfavorable conditions may 
weaken their power or virulence. 

The bacteria which are the cause of typhoid, diph¬ 
theria, or tuberculosis make a specialty of this work. 
The true parasitic disease germs affecting man must 
have human beings in which to propagate with any 
degree of success; so the human body is the chief 
natural breeding ground of contagious disease germs . 



Origin 
of Disease 
Germs' 


Breeding 
Ground 
for Germs 


78 


HOUSEHOLD BACTERIOLOGY 


Point of 
Attack 


Method of 
Infection 


Precautions 


Outside of the body disease producing bacteria may 
remain alive under very varying circumstances, but as 
a rule they do not multiply as most of them require a 
temperature equal to that of the body. There are ex¬ 
ceptions, as, for example, the growth of the bacteria 
of typhoid fever in milk, and many others which 
reproduce in the laboratory under artificial conditions. 
The lower animals may serve as a breeding ground 
for some of the disease germs dangerous to man. 

For most of these germ diseases there is some spe¬ 
cial portion of the body which is more susceptible than 
any other. We associate pneumonia and usually tu¬ 
berculosis with the lungs, diphtheria with the throat, 
typhoid fever with certain parts of the intestines. From 
these most usual points of attack may be inferred the 
most common methods of infection. 

When the seat of the disease is some portion of the 
respiratory system—nostrils, throat or lungs—it is 
probable that dust entering with the inhaled air car¬ 
ried the germ, or it came by contact with the lips, as 
in kissing; when it is in the digestive tract, that food 
or drink was the vehicle; or when in the skin or outer 
tissues, that there was actual contact with the germ 
either as dust, dirt, or germ bearing material from a 
previous case of the disease, which gained entrance 
through some puncture or a break in the skin. 

When we remember that all such diseased condi¬ 
tions due to germs are infectious, we shall exercise 
great care in preventing contact with the diseased 


DISEASE GERMS 


79 


part or with articles which have come into contact 
with it. It should prevent the use of the mouth as a 
“third hand” for holding miscellaneous articles; the 
moistening with saliva of envelopes or of fingers to 
turn leaves, etc., which thence may carry infection to 
the next user. We should think of the danger to 
others as well as to ourselves. 

This is one of the objections to a common comb 
and hairbrush, towel, etc. All ready-made gar¬ 
ments worn next the skin should be washed before 
wearing. All garments made under “sweatshop” con¬ 
ditions should be avoided, because of the danger of 
contagion, if for no other reason. Clothes subject 
to any infectious discharge, as handkerchiefs, towels, 
etc., should not be washed with other clothes. When 
possible, all such discharges should be received upon 
paper or cloths that can be burned immediately. It 
is well to take this much forethought for the laun 
dress. 

Especially with such diseases as tuberculosis, pneu¬ 
monia, and diphtheria, absolute care should be taken 
that the sputa or discharges from the nostrils and 
throat as in sneezing or coughing, are not thrown off 
into the air to become a part of the common dust. 
When the person himself is able to control the dis¬ 
charge he should remember that he may thus re-in- 
fect himself and also spread the disease. Infected or 
soiled articles should be immediately disinfected, 
burned, or boiled. If this cannot be done at once, 


Care of 
Discharges 


8o 


HOUSEHOLD BACTERIOLOGY 


Lockjaw 



they should be kept wet, then the germs cannot easily 
be spread about except by flies. 

An exception to the usual characteristics of disease 
producing germs is a bacillus which is common in the 
soil of certain localities,—the germ of the usually 
fatal disease known as tetanus or lockjaw. Fig. 43. 
The living germ or its spore is carried into the warm, 
moist tissues through a wound in the skin. This us¬ 
ually is made with some sharp object which has come 
in contact with the ground, as a nail, a rake tooth, 
a pitch-fork, or a dirty knife. 
It has been known to follow 
the bite of an insect. Unlike 
most disease germs, this bac¬ 
terium forms spores which 
makes it very tenacious of life. 
Its spores will resist boiling or 
drying for some time. It is 
said to have been found in gun¬ 
powder which would account 
for the many cases of lock¬ 
jaw resulting from gunshot 
wounds. As a result of celebrating the Fourth of July 
in 1903, 415 deaths from lockjaw occurred in the 
United States. This number dropped in 1904 to 105, in 
1905 to 104, and in 1906 to 89. This decrease was 
brought about through the proper care of wounds and 
the use of tetanus antitoxine. Wounds should be 
cleaned thoroughly and not bound up tightly, as the 



FIG. 43. The Bacillus 
of Lockjaw. 


DISEASE GERMS 81 

exclusion of air favors the growth of the tetanus ba¬ 
cillus. Its characteristic spore at one end of the rod 
has given it the name of the “drum stick” bacillus. 

In general it may be concisely stated that infection 
comes through inhaled dust and that “Food and fingers 
are the carriers of contagion,” as Dr. William T. 
Sedgwick has so often proved. 

The disease bacteria effect their dread results in 
various ways; sometimes the tissues are actually de¬ 
stroyed, as in tuberculosis, but in most cases the prod¬ 
ucts of the life growth of the germs cause the disease. 
These products are poisons which are known under the 
general name of toxines. 

Whether in the future the germ theory will be found 
to explain all diseases we may not now say, but indi¬ 
cations point that way. The latest “discovery of the 
germ of smallpox,” if established, is a stimulus to 
increased efforts along such lines. Animal and vege¬ 
table forms are both proved guilty before the bar of 
the scientific investigator. 

The germ of typhoid fever grows well in milk. 
The germ may enter the milk as dry dust from any 
one of many contaminated sources, or through water 
in which the milk-containing vessels are washed. In 
cases of dishonest milkmen, from the water used to 
dilute the milk. Numerous epidemics of typhoid fever 
have been traced to milk as their source, where only 
those using milk from one farm or from a certain 
milkman have been affected. 


Typhoid 
Infection 
by Milk 


Infection 
by Oysters 


Sewage 


82 HOUSEHOLD BACTERIOLOGY 

That the germ may retain its vitality through all 
the processes of butter-making is proved by its pres¬ 
ence in samples of butter examined. 

It is not always easy nor possible to find the source 
of single cases of this or any disease, for the infectious 
germ, carried as dust, may lodge on any article and 
be thus carried to the mouth by food or by hands; 

Oysters, fattened on sewage-polluted water, have 
carried the germ to persons eating them. Clams dug 
out of sewage-saturated flats, when eaten raw, may 
carry the typhoid germ in a similar manner. 

In country places where wells are the source of 
drinking water, or anywhere where surface waters are 
used directly for this purpose, there is great danger 
of contamination from drainage, either from the house, 
its outbuildings, the barn, or manured fields. Con¬ 
taminated water supply is the most common source of 
typhoid infection. 

As the germs causing the disease are thrown out in 
the discharges from the intestines and the kidneys, 
these are the sources of infection. If the discharges 
from the patient and any articles soiled, by these are 
not destroyed by fire or thoroughly disinfected while 
moist, there can be no surety that they may not, either 
as dust or through water, carry infection to someone 
nearby or even far removed. If such care be taken 
for every case of the disease, it will soon be no more 
prevalent than smallpox. 

Eicry case of typhoid fever is due to somebody’s 


DISEASE GERMS 


83 


criminal carelessness, because in the eye of the law 
ignorance is not accepted as an excuse. Somewhere 
there has been neglect of the cleanness or care which 
ought to have made infection impossible. 

When rain starts from the clouds it is pure, but in 
falling through the air it washes out from the air large 
quantities of dust, so that the first fall of any shower 
is very dirty. Where rain water is collected for drink¬ 
ing or cooking purposes this first fall should be allowed 
to waste or the whole be thoroughly filtered before 
its use in cooking. The cistern also must be kept clean 
and free from dust pollution. It should be sheltered, 
but not air-tight. Such a water supply is seldom pol¬ 
luted by sewage or any human wastes. It is water 
running on the surface of the ground or draining 
through it which may encounter sewage pollution and 
thus be most liable to take up disease germs. 

Snow filters the air even more than rain, each con¬ 
gealed flake usually containing many bacteria. The 
first snow, although white and pure to look at, is not 
clean and should not be used as a source of drinking 
water except in emergencies. However, after the snow 
has been falling for some time the water from it is 
practically clean. 

Light always retards and in many cases prevents 
the development of harmful micro-organisms. But this 
disinfectant action does not extend to all depths, prob¬ 
ably not much beyond nine feet, so that its purifying 
agency in open water supplies is only partial. A water 


Criminal 

Carlessness 


Pollution 
of Water 


Effect 
of Light 


8 4 


HOUSEHOLD BACTERIOLOGY 


Purifying 

Water 

Filters 


Porcelain 

Filters 


supply which receives any house drainage or that from 
manured fields is in danger of contamination at any 
time. 

Impure water may be purified from all germs by 
boiling for half an hour. Such water, having lost 
the air which was dissolved in it, tastes insipid. The 
air may be restored by pouring the water a few times 
from one clean vessel into another, and this should be 
done in a clean place, that is, where there is little fly¬ 
ing dust. 

Most filters simply strain out visible suspended mat¬ 
ter or invisible but comparatively large animal or veg¬ 
etable forms. A flannel bag will do this, and it can 
and should be cleaned daily. It clears currant jelly, 
why not water? When charcoal forms a part or the 
whole of the straining medium, more organic matter 
is removed and therefore more color is taken out, but 
the charcoal soon loses its purifying power and must 
be cleaned or renewed. None of the ordinary faucet 
filters will remove the minute disease germs and there¬ 
by make a polluted water safe for drinking. Germ 
removal requires a very fine medium, which means 
slow straining. Certain filters, made of very fine un¬ 
glazed clay or similar substance, take out the germs 
themselves, but cannot remove the products of their 
life processes, which are soluble. In some cases these 
are as dangerous as the germ plant itself. If a filter 
does strain out the bacteria, then it is evident that 
the straining medium will become foul with them and 


DISEASE GERMS 


85 


must be capable of and receive complete sterilization. 

Any faucet filter which allows a generous stream of 
water to issue quickly after it is turned on is practical¬ 
ly useless so far as the removal of bacteria is con¬ 
cerned. 

A suspected water or one of unknown quality would Filter 
better be filtered and then boiled rather than boiled ajid Boif 
filtered, if it needs to be filtered to remove suspended 
matter. Distilled water or water turned into steam 
and condensed is a pure water; but to remain so it 
must be received into perfectly clean vessels and not 
exposed to dust. 

Ice as ordinarily delivered frequently shows three Ice 
layers. One, usually at the top, the snow ice, is scarce¬ 
ly transparent and when melted shows impurities not 
visible in the ice. This usually holds many bacteria 
and should always be rejected. Another layer, par¬ 
tially transparent, is more or less bubbly. These 
bubbles contain air which allows any living forms 
therein to remain alive if not to grow. If derived 
from impure water the bubbles may contain some 
of the germs which will make the ice undesirable, 
since many bacteria survive a lower temperature than 
ice ever attains. A third portion is wholly trans¬ 
parent. This last, the crystal clear ice, is the only ice 
which should ever be used directly to cool drinking 
water, for this alone is purified by crystallization al¬ 
though not perfectly. 

Ice should always be washed from surface dirt before 


86 


HOUSEHOLD BACTERIOLOGY 


Sources of 
Infection 


it is put into a refrigerator or in any way used for the 
storage of food. Safety may be assured if ice is never 
allowed to touch the food. Its effects can be obtained 
without actual contact and contact may mean con¬ 
tamination. 

The tub of lemonade standing open on the picnic 
ground or the street corner has sufficient chance of 
germ infection without a block of doubtful ice in its 
midst. 

THE RESISTANCE OF THE BODY TO DISEASE GERMS 

We have seen that many diseases which afflict hu¬ 
man beings have been definitely traced to these or¬ 
ganic forms; to these micro-organisms found in in¬ 
haled dust, in polluted water, in food and on articles 
which may puncture the skin. 

If the avenues of infection are so common, the ques¬ 
tion naturally arises, how can any human being escape ? 
We know that many do, that there are hundreds of 
persons who never have had typhoid fever, diphtheria, 
or other infectious disease; that two persons may, so 
far as we know, eat of the same food, drink from the 
same water supply or live under exactly similar con¬ 
ditions—one has some infectious disease, the other re¬ 
mains well. 

It is too a matter of common knowledge that a de^ 
gree of safety from a second attack is often assured to 
the person after recovery from the first illness. He 
seems to have some power of resistance which he did 
not have before and which is absent in his neighbor. 


RESISTANCE OF THE BODY 


8 7 


Yet this safety is not always complete, because some 
persons have recurring attacks of infectious diseases. 
This is especially true in diphtheria. 

There seems to be some power in the robust, healthy, 
strong body which is absent in the weak and “ailing” 
or in the body “below par,” as the physicians say. 
Whatever this power is it may well be referred to as 
“vital resistance.” 

Dr. William Sedgwick says, “There is, however, no 
quantitative measure of vital resistance; but when it 
is regarded as small or altogether wanting, the term 
is no longer used, and the organism is said to be not 
vitally resistant, but “susceptible” or “vulnerable” to 
disease. * * * When the vital resistance is com¬ 
plete * * * the organism is said to be immune ” 

At present no one perhaps knows all the factors 
which go to make up this “vital resistance” which pro¬ 
tects one person and is absent in another, but accord¬ 
ing to Sedgwick, “We may, it is true, safely consider 
that it is bound up with chemical and physical pro¬ 
cesses which result in favorable chemical and physical 
conditions.” 

In this connection it should be noted that the hy¬ 
drochloric acid in the gastric juices of the adult is 
fatal to nearly all of the ordinary bacteria present 
in uncooked food and to many disease germs. The 
secretions of the intestines are alkaline and would prove 
a favorable condition for many kinds did they escape 
from the stomach. Water passes quickly through the 


Vital 

Resistance 


Gastric 

Juices 


Health 


Theories 
of Vital 
Resistance 


Leucocyte 


88 HOUSEHOLD BACTERIOLOGY 

stomach and may not mix with the acid juices, con¬ 
sequently it is an especially dangerous medium of in¬ 
fection. 

Health means the prevention in all possible ways of 
any chance of attack from the insidious disease germ, 
but it means as well the observance of all other laws 
that tend toward the maximum efficiency of the body 
and mind , so that if the enemy gains admittance it may 
be routed or its attack made futile. 

Much has been done along the lines of investiga¬ 
tion, yet much of these processes of resistance remain 
to be proved. A few words concerning the theories 
put forth by investigators may show our indebtedness 
to them and increase our own sense of responsibility 
toward the preservation or return of health. 

Among the red cells which give the familiar color 
to good, rich blood are other cells known as the white 
globules or leucocytes . They are very much like the 
amoeba, the lowest animal known, in that they have 
the power of independent motion. They are some¬ 
times called “phagocytes,” or “wandering cells,” be¬ 
cause they pass here and there throughout the body, 
wherever they will. Fig. 44. Their office seems to be 
a protective one, for they act like the police of a city 
in protecting the body from bacterial invaders. They 
are also called “eating cells,” for when one finds a bac¬ 
terium it proceeds to wrap itself about the little plant 
cell, to poison, if not to kill it; then, loaded with the 
dead bodies of its victims, it makes its way to some 
part of the body where the load may be disgorged. 


RESISTANCE OF THE BODY 


89 



FIG. 44. (a) and (b). PHAGOCYTES. 

(c) A phagocyte with partially enclosed bacterium. 

(d) A phagocyte with two bacteria enclosed. 

(e) A phagocyte with enclosed mass of bacteria. (After Conn.) 



go 


HOUSEHOLD BACTERIOLOGY 


Effect 
of Cold 


Formation 
ox Pus 


It is fortunate for us that there is such a force that 
is hungry and ever seeking what and how many it 
may devour, for we can never know just how much 
we owe to them for our freedom from disease. As 
long as these white globules are numerous and active, 
so long man seems to have one powerful guardian 
against any invading germ, however poisonous. Any¬ 
thing which affects these white guardians unfavorably 
lessens their power to protect man. 

Cold paralyzes them and gives the bacteria, if pres¬ 
ent, a better chance to escape from being overcome, 
and we are thus more subject to their attacks. Win¬ 
ter’s cold increases the prevalence of many germ dis¬ 
eases, not usually by increasing the number or virulence 
of the germs themselves, but by decreasing in some 
persons the power of these leucocytes—the guardians 
of our health. 

Insufficient clothing, or insufficient food which is 
the body’s fuel, may thus favor the attacks or the 
spread of germ diseases. Very often these phagocytes 
lose their lives in resisting our foes. Then they, with 
their victims and the dead tissue cells, form pus or 
“matter,” which children even know should be “let 
out” in order that the tissues may heal. 

The formation of pus is well illustrated by the 
action of a sliver. We may or may not know that the 
tiny speck of wood entered the flesh. But it is likely 
to carry in with it dirt and therefore bacteria. The 
phagocytes rally to surround this newcomer. The flesh 


RESISTANCE OF THE BODY gi 

becomes red, inflamed and sore, then a “fester” ap¬ 
pears. Open the “fester” and a drop or more of pus 
exudes, in the midst of which will probably be the 
irritating sliver. The bacteria, the cause of the inflam¬ 
mation, having passed out, the flesh heals. If there 
has been much bacterial growth there may be much 
or longer continued inflammation because of the tox- 
ines or poisonous matters produced by the germs. 

When certain very virulent germs enter the tissues, 
are unconquered either by the phagocytes or the other 
resisting powers of the body, the products of germ 
growth may be rapidly distributed by the blood 
throughout the body, producing the fatal cases of blood 
poisoning. The germ was especially virulent, in great 
numbers, or possibly neither of these, but the body was 
so “far below par” that it had no power to resist the 
growth and action of the germs and the toxines which 
the germs manufactured. 

That bacteria capable of producing disease in human 
beings are far more commonly present than the diseases 
cannot be doubted. Germs of pneumonia are found 
in the mouths of healthy persons. Some persons when 
exposed to infection succumb; others remain unaf¬ 
fected. The old saying that “lightning never strikes 
twice in the same place” has often been applied to the 
expressed fear of a recurrence of an infectious dis¬ 
ease. Although there are many exceptions to the rule, 
it is true, as we have said, that in a majority of cases 
after recovery from such a disease there is less dan- 

i 


Blood 

Poisoning: 


Germs 

Without 

Disease 


92 


HOUSEHOLD BACTERIOLOGY 


Effect of 
Poisoning 


Immunity 


ger of a second attack. There seems to be great dif¬ 
ferences also between the susceptibility of children and 
adults to certain diseases. 

The different ways in which bacteria are known or 
supposed to bring about diseased conditions more or 
less severe have been described. Whether these 
causes are the poisonous excretions during the nor¬ 
mal life of the bacteria, of are the result of chemical 
change produced by some ferment which they secrete, 
the effects upon the blood and tissues are shown by 
several common symptoms—a high temperature or 
fever; quickened circulation or rapid pulse; perhaps 
difficulty in breathing, and pain. There may be local 
redness, swelling, and finally the formation of pus, or 
a “gathering” of the protective phagocytes and the 
broken-down cells of the diseased portion. These local 
effects may be entirely within the body or they may be 
show themselves on the outside under or in the skin. 
In the latter case a prompt discharge of the pus is 
usually followed by relief. If there be no discharge, 
and the dead and poisonous matter be reabsorbed into 
the tissues, there follows a general poisoning of the 
whole system. 

Whenever partial or entire immunity seems to be 
present, we are interested to know in what this im¬ 
munity consists. Great as is the protective force of 
the “white guardians” their presence or numbers are 
not the only factors in immunity. 

Metchnikoff, the father of the theory of phagocy- 



RESISTANCE OF THE BODY 


93 


tosis —as the protective work of these “eating” and 
“wandering cells” is called—has said that “immunity 
may be inborn or acquired.” * * The former is 

independent of the direct intervention of human art; 
the acquired immunity may come as the result of the 
spontaneous cure of an infectious disease or as the 
result of direct interference of human art, as in vac¬ 
cination and similar methods now employed by phys¬ 
icians to ward off an expected disease or to decrease 
the virulence of one already contracted.” 

This inborn immunity Newman calls “natural im¬ 
munity” and attributes it to the presence in the blood 
of soluble matters called alexines. If the alexines are 
present in sufficient quantity, the person is less or not 
at all susceptible to certain diseases, although they may 
not protect him from the attack of all disease germs. 
These alexines protect the body perfectly from all 
but the pathogenic bacteria. 

Phagocytosis seems to be a plausible theory so far 
as the germs themselves are concerned, but does not 
prove equally tenable in the case of the toxines which 
the germs have produced. Other investigators, 
notably Behring and Kitasato, do not believe that the 
phagocytes are the prime protective agency in this 
immunity. They discovered in their experiments upon 
animals that the clear, yellowish liquid part of the 
blood, or the bloom serum, taken from an animal that 
had diphtheria could and did in their test tubes destroy 
the action of the toxines of that disease. 


Natural 

Immunity 


Toxine 


94 


HOUSEHOLD BACTERIOLOGY 


Antitoxine 


Acquired 

Immunity 


Vaccination 


It seems, then, probable that in the blood serum of 
immune persons there may be another factor in the 
vital resistance. That is, the body cells in some way 
manufacture substances that neutralize the poisons or 
toxines produced by the germs, thus enabling the body 
to expel the germs themselves, and recover. These 
cintitoxines or the power of producing them may re¬ 
main and the body becomes immune to the disease. 
These antitoxines are specific in nature,—that is, are 
capable of neutralizing the toxine of only one kind of 
germ. 

Immunity may also be “acquired” by the injection 
into the blood, in some cases, of the germs themselves, 
as in the case of inoculation for small pox as was 
as was originally done in the case of inoculation for 
small pox. Formerly some “matter,” that is, the in¬ 
fectious material, was taken from a person sick with 
small pox and injected directly into another person by 
placing it under the skin, where it quickly afifected the 
whole body. 

Jenner—a celebrated doctor in England about 1796 
—first modified inoculation by introducing the “mat¬ 
ter” into healthy calves or cows. These animals be¬ 
ing very susceptible to the disease, contracted it, and 
then from the pustules of their bodies the “matter” 
or “vaccine” was drawn and injected into human be¬ 
ings. This, in man, was found to produce a milder 
form of the disease and to leave in the system upon 
recovery something which gave immunity or protec¬ 
tion from small pox. 


RESISTANCE OF THE BODY 95 

Vaccination or Jenner’s process is still the recog¬ 
nized preventive or protective measure, and it has re¬ 
duced small pox from a dread pestilence to a disease 
producing fewer deaths than measles. 

The great Pasteur reasoned that “if an infectious 
disease be really a struggle for supremacy between 
man and microbe, it is probable that in vaccination for 
small pox the struggle is less severe for the patient, 
because the germs of small pox have somehow been 
weakened or enfeebled by their residence in the cow/’ 

The use of antitoxine for the prevention or treat¬ 
ment of diphtheria is perhaps the best example of that 
method of producing immunity. In this case the horse 
is chosen as the intermediate host for the production 
of antitoxine material. The toxines, or sometimes 
the germs themselves, are injected into the body of 
the healthy animal. The first dose is usually a small 
one. A slight reaction or fever may be noticed. The 
doses are gradually increased until the animal is found 
to be immune. Blood is then drawn from this immune 
horse and “its serum is found to contain the anti¬ 
toxine in abundance.” 

Some of this serum is then injected into a per¬ 
son who has been exposed to, is likely to be, or is 
ill with the disease. In the last case, to be effective, 
the antitoxine must be introduced at an early stage of 
the disease when there is not too much toxine to be 
neutralized. 

By the use of antitoxine thus obtained, the mortality 


Making 

Antitoxine 


Diphtheria 

Antitoxine 


96 


HOUSEHOLD BACTERIOLOGY 


Nature’s 

Disinfectants 


Conditions 
in the House 


from diphtheria has been reduced over one half. Its 
effects as a preventive measure and in lessening suffer¬ 
ing “have everywhere been most significant and en¬ 
couraging.” Antitoxines for lockjaw, for snake bites 
and for some forms of blood poisoning have been pro¬ 
duced and are used with more or less success. 

Constant efforts are being made to find an available 
antitoxine for every infectious disease. Many diffi¬ 
culties present themselves, because the same germs do 
not always cause the identical disease when introduced 
into the bodies of the lower animals that they produce 
in the body of man. 

SANITATION 

As sunshine and pure air are Nature’s free disin¬ 
fectants, their presence in the house is the greatest pre¬ 
ventive measure of all sickness due to micro-organ-' 
isms. They, then, are the foundation requirements 
for cleanness, because this means so largely the ab¬ 
sence of dust-plants. 

Inside our houses there can never be the same 
amount of sunshine and fresh air that proves so ef¬ 
ficient out-of-doors. The house, too, must be dry, and 
therefore dust cannot be held as it often is out of 
doors on damp surfaces. However, the absence of 
winds inside makes possible, after a little while, a com¬ 
paratively dust-free air, because the heavier particles 
which carry the bacteria and molds will settle on all 
surfaces, chiefly on the horizontal ones, as floors, 


SANITATION 


97 


chairs, shelves, etc. Figure 45, redrawn from Dust 
and Its Dangers, T. Mitchell Prudden, shows how the 
living plants attach themselves to the other particles 
of dust ; a is a small bit of wood carrying four different 




45. COLONIES OF BACTERIA GROWING ON DUST PARTICLES. 
(After Prudden.) 

colonies ; b is a grain of sand surrounded by one col¬ 
ony ; c a splinter of wood, is loaded with five different 
species. Each of these colonies is the growth of five 
days from a single germ which fell on the surface of 
the gelatine. At the end of five days the largest was 
only just visible to the naked eye. 

If a dust-garden be planted immediately after 


Sweeping 






98 


HOUSEHOLD BACTERIOLOGY 


Dust Gardens 


Settling 
of Bacteria 
and Molds 


sweeping a carpeted room and another when the same 
room, with closed windows, has been left undisturbed 
for two or three hours, there is a marked difference 
in the number and kind of colonies which will grow. 

Figures 46 to 49 inclusive are photographs of “dust- 
gardens” planted in various places by different persons 
under varying conditions. The plate shown in Fig. 
46 was planted after a carpet had been swept with a 
dampened broom. The plate was left open ten 
minutes. 

The damp broom caught and held much of the dust 
which would have been thrown into the air if a dry 
broom had been used. If the sweeping had been done 
carelessly without thought of the dust, many more 
plants would have found their way to the garden plot. 
As it was, the number of spots shows how carefully 
sweeping ought to be done in order that the air may 
not be charged with dust which is thereby simply 
changed in place, not removed from the room. It 
soon returns to the floor or carpet. 

Plate Fig. 47 was exposed for ten minutes in the 
same place after the room had been quiet for three 
hours and the dust had therefore settled considerably. 
The fewer spots show that the air had become much 
freer from dust than when Fig. 46 was planted. 

The greater number of molds present in this plate 
shows that the bacteria, being heavier, settle first. The 
presence of so many molds shows that even after 
three hours’ quiet, the air may still be sufficiently 


SANITATION 


99 



FIG. 46. A PETRI PLATE PLANTED IMMEDIATELY AFTER THE 

SWEEPING OF A CARPET. 


> 

) 

i 


ty 


> t 

> > t 




100 


HOUSEHOLD BACTERIOLOGY 


Time for 
Dusting 


charged with dust to cause trouble if food is un¬ 
covered. 

Many interesting experiments have been carried on 
in hospitals to find how long it takes for the bacteria 
to settle out of the air of the wards after the daily 
routine of cleaning and care is over, or at night. 

In the Boston City Hospital* it was found that about 
midnight after the wards had been quiet for some 
hours the bacteria had nearly all of them settled upon 
the floors, beds, or other articles of furniture. As soon 
as the work of the day begun many of these, of course, 
were again thrown into the air. Dr. Tucker found 
that sweeping nearly doubled the number of germs 
found in the air. 

In some experiments reported by Dr. T. M. Prud- 
den f it was found that in a carpeted living room 
75 bacteria and i mold settled on the surface of the 
exposed plate in five minutes before sweeping, when 
the room was still. Immediately after sweeping, a 
similar experiment showed over 2,760 bacteria and 
6 molds. 

3* ■ -f 

Other experiments have compared the numbers 
found in a certain quantity of air taken from houses 
considered clean and those called dirty. The latter 
showed about six times as many bacteria as the 
former. 

Compare Fig. 46 with Fig. 47 and decide the ques- 

*Report of State Board of Health of Mass., 1888. 
jDust and Its Dangers, T. Mitchell Pruden. 



SANITATION 


IOI 


i 

S. 47. THE SAME AS FIG. 4G, AFTER THE DUST HAD SETTLED 

THREE HOURS. 








102 


HOUSEHOLD BACTERIOLOGY 


Bed-making 


tion when dusting should be done, if the aim of dust¬ 
ing be to remove dust from the house. If, then, these 
and other experiments have shown that at least two 
hours are required to free the air of a still room from 
the bacteria present in its dust, it is of little use to 
dust immediately after sweeping. When this is done, 
no wonder the housewife exclaims in despair, “Why, 
this room was dusted this morning, but you never 
would have known it!” 

While we cannot always let two hours elapse be¬ 
tween some dust-spreading process of housework, like 
sweeping or bedmaking, we can remember that the 
raised dust must settle before we can remove it. Wait 
as long as possible! 

When Fig. 46 is compared with Fig. 47, the reason 
is plainly seen why rugs mean less dust than carpets 
and therefore a cleaner, healthier house, because these 
can be carefully rolled, cleaned out of doors, and the 
floor wiped with a damp cloth. 

Next to sweeping as a dust-raising and dust-spread¬ 
ing process comes bed-making. 

Fig. 48 shows a plate planted just after a bed had 
been made. The colonies of bacteria and molds in this 
plate had been growing for a longer time when the 
photograph was taken than in plates Fig. 46 and Fig. 
47. Two of the molds on this plate are very mature, 
being black with spores. 

As health requires that the air of the sleeping room 
be as free from dust as possible, considerable time 


SANITATION 


103 



FIG. 48. DUST GARDEN PLANTED IMMEDIATELY AFTER BED 

MAKING. 











Removing 

Dust 


Burn 

Sweepings 

Wash 

Dusters 


Cover 

Food 


104 HOUSEHOLD BACTERIOLOGY 

should elapse after bed-making before the dusting is 
done. 

To have a clean house, great attention must be paid 
to the removal of dust, or dusting. In houses where this 
is done with a feather duster, bed-making gives up 
its second place to this dust-spreading, never a com¬ 
plete dust-removing process. Dusting should always 
be done by wiping up the dust into a cloth. When¬ 
ever possible to do so without harm, the cloth should 
be slightly dampened or oiled. Dust-plants are held by 
damp or oiled surfaces. 

If, then, the bacteria do settle from the air on floor 
and furniture, and in still places about two hours is 
necessary to effect this comparative clearing of the 
air, these facts are surely indicated: 

First. Sweeping should be done in such a way as 
to raise as little dust as possible into the air. 

Second. Dusting should never follow immediately 
after sweeping. 

Third. Dusting should be a process whereby dust 
is taken out of the room, not stirred up and thrown 
again into the air. Cleanness does not result unless 
the dust is removed from the house. 

All collections of dirt from sweeping should be 
burned, and all dusters should be washed. “Burn the 
sweepings” and “wash the dusters” are two orders 
which the intelligent housewife will obey. 

Dust in the air settles on food and thus produces 
decomposition. Food then should be kept covered as 


SANITATION 


105 



FIG. 40. DUST GARDEN PLANTED OUT OF DOORS 





Brush 

Clothing 


Deadly 

Dish-Cloths 


Care of 
Plumbing 


106 HOUSEHOLD BACTERIOLOGY 

much as possible, cold and dry as feasible, to retard 
the growth of the micro-organisms present. All foods 
eaten raw should be thoroughly cleaned, especially 
those that have been exposed to dust, those grown in 
or near the earth or those watered by house slops. 

Clothes should be well brushed, out of doors if pos¬ 
sible ; those which can be should be washed frequently, 
boiled and sunned. All should be kept dry to prevent 
mildew, which we know is mold. 

That dish cloths and dish towels be kept clean is as 
necessary for health as for clean, bright tableware. 
The. greasy dish cloth furnishes a most favorable field 
for the growth of germs. It must be washed with 
soap and hot water and dried thoroughly each time. 
All such cloths should also form a part of the weekly 
wash and be subjected to all the disinfection possible 
with soap, hot water, and long drying in sunshine 
and the open air. Beware of the disease-breeding, 
greasy, and damp dish cloth hung in a warm, dark 
place! Indeed, no damp article should ever be stored 
in the dark. The ordinary sink cupboard is a warm, 
dark and usually a damp place, which even the plumber 
denounces as an unclean spot. 

All waste and overflow pipes, from that of the 
kitchen sink to that of the refrigerator, become foul 
with grease, lint, dust, and many organic compounds 
that are the result of bacterial action. They are 
sources of contamination to the air of the entire house 
and to the food supply, thereby endangering health. 


SANITATION 


107 


The germs of putrefaction abound in dark places 
and the air becomes stagnant and impure. 

As the schoolroom bears very close relations to the 
home, the conditions there should be thought about by 
the housewife. Either from lack of time or money, 
wrong methods, or too few employees, the so-called 
cleaning of many schoolrooms consists in a vigorous 
sweeping with dry broom or floor brush after school 
at night. The dust settles during the night, but in 
the morning, instead of being taken away on damp or 
oiled cloths, it is stirred into the air again by the 
whisking feather dusters. 

At nine o’clock, in troop the children, with warm, 
moist throats, eyelids, and nostrils all ready to catch 
the floating germs which should have been removed . 

The housekeeping of schoolhouses needs intelligent 
supervision as well as the mental and moral equip¬ 
ment of their inmates. Where so many persons are 
gathered from many kinds of homes the danger from 
the presence of disease germs must be greatly in¬ 
creased over that of the private house. 

In dirty schoolrooms, poorly ventilated by windows 
and doors, compared with well ventilated rooms, the 
proportion of bacteria in the same volume of air has 
been found to be sometimes as great as si’- & one 
hundred. 

The cleaning and cleanness of schoolrooms should 
certainly interest mothers, next to that of their own 
homes. This may be their first civic duty. 


Cleaning 
School Rooms 


Sanitary 

Cleanness 


ioR HOUSEHOLD BACTERIOLOGY 

Sanitary cleanness requires the cleanness of the in¬ 
dividual, of his possessions, and of his environment. 
Each individual is directly responsible for his per¬ 
sonal cleanness and that of his possessions; but over a 
large part of his environment he has only indirect 
control. Not until this personal responsibility is felt 
in its fullest sense, and exercised in all directions to¬ 
ward the formation and carrying out of sufficient and 
efficient public laws, will sanitary cleanness supplant 
the cure of a large number of diseases by their pre¬ 
vention. 

When the right of cleanness is added to the right to 
be well fed, and both are assured to each individual 
by the knowledge and consent of the whole people, 
then the great gospel of prevention may make good 
its claim. Towards this ideal tend all the problems 
which the science of bacteriology is endeavoring to 
solve. These problems cannot be solved in the labora¬ 
tory alone. Each house in the land, presided over by 
an active, intelligent supervisor, should become an ex¬ 
periment station for the individual application of 
scientific laws. 


HISTORY OF BACTERIOLOGY 


The science of Bacteriology is still young, and like 
normal youth is marked by constant, vigorous growth, 
yet the micro-organisms with which it deals are veri¬ 
tably antique, for the following quaint observation is 
said to have been made two thousand years ago: “It 
is to be noticed that if there be any marshy places, 
certain animals breed there, which are invisible to the 
eye and yet, getting into the system through the mouth 
and nostrils, cause serious disorders.” 

Later on when the early scientists were looking 
through their very imperfect lenses at certain liquids, 
they saw many hardly visible moving bodies. They 
said, “Surely these moving things must be alive,” and 
as they had not put anything into the liquids, it was 
natural to conclude that the little forms must have 
been spontaneously generated. So great a thinker as 
Aristotle had previously made a similar statement, for 
when he saw birds one morning flying about over the 
valley of the Nile, where the day before not a bird 
was present, he devoutly concluded that they must 
have been generated from the mud of the Nile, that 
great Father of Plenty. It is within the memory of 
some living today that this theory of spontaneous 
generation was still believed. 

About 1675 Leuwenhock, the son of a Dutch lens 
grinder, saw through one of his lenses in a drop of 
stagnant water minute moving forms. Soon some of 
the scientists became interested and studied these “ani¬ 
malcules” or little animals, as they were called. They 


Spontaneous 
Generation 
of Life 


Animalcules 


109 


Early 
Theory of 
Fermentation 


Ueadow 

Tea 


no HOUSEHOLD BACTERIOLOGY 

made drawings of what they saw, which show very 
much the -same forms that would be seen today under 
similar conditions. Many scoffed at these reports, in¬ 
timating that such observers were not wholly sane. 

The processes of fermentation and putrefaction very 
early excited investigation. Great efforts were made 
to find out their cause. For years the oxygen of the 
air was thought to be the agent, and even today many 
a housewife will tell you the jar of fruit spoiled be¬ 
cause “the air got into it.” The dust-plants which are 
in the air, the real cause of these changes, could riot 
be discovered until the compound microscope brought 
to view the hitherto invisible life which swarms in all 
fermenting and putrefying matter. 

The compound microscope was invented in the early 
part of the seventeenth century, by whom is not 
known. It was not brought to its present simple but 
effective form until about sixty years ago. 

One of the first sources of bacteria for these early 
investigations is still a common and sure source. 

Take a wisp of hay and soak it in lukewarm water 
for a day or so. The result is a brownish liquid look¬ 
ing much like tea, which it is, being an infusion of 
hay. Thoreau called this “meadow tea.” A drop of 
this under the microscope furnishes a lively menagerie, 
as well as numerous bacilli. The hay is dusty; in the 
dry dust are spores of bacteria which under the influ¬ 
ence of the warmth and moisture become once again 
active forms and can be seen to go through all their 
life processes. 


HISTORY OF BACTERIOLOGY 


iii 


A drop of water from the neglected vase of flowers 
will often give similar interesting phenomena. 

The modern work upon bacteria was begun and the 
foundations of the science of Bacteriology were laid 
when Louis Pasteur in France, less than sixty years 
ago, began to grow and cultivate these dust-plants. 
Since then the advance in knowledge about them has 
gone on with ever increasing rapidity. 

If it is possible to increase the power of the micro¬ 
scope or to so train the human eye that it may see 
more than is seen at present, would greater wonders 
be revealed? Such a possibility is ever before the en¬ 
thusiastic student. 

About twenty years after Pasteur, Robert Koch de¬ 
clared that he believed bacteria were the cause of dis¬ 
ease and not the effect, as many had thought them to 
be. He began to grow bacteria on potatoes and in 
other ways then new, but now common. These are 
known as “solid cultures. ,, 

This was a great advance toward the discovery of 
disease germs, because by the differences in their be¬ 
havior or growth on different substances it was pos¬ 
sible to separate the species. 

The farmer knows that the same soil is not equally 
good for corn and melons and that a pine tree will 
flourish where a willow would die. These are at the 
other extreme in the plant world from the invisible 
bacteria, but the microscopic forms have their prefer¬ 
ences in food and their favorable and unfavorable 
conditions, as well as their well-known giant brothers. 


Work of 
Pasteur 


Koch’s 

Theory 


II2 


HOUSEHOLD BACTERIOLOGY 


Method 
of Study 


i. 


h A:-» : 

Bacteria 

Classed 

as Plants 


Founding: 
of the 
Science 


By finding what they grow on and their behavior in 
different soils; what they like best to eat; what tem¬ 
perature is most favorable to reproduction; adding to 
this the knowledge of structure, motion, and form 
which the microscope reveals, and lastly by chemical 
analysis of the substances produced by them during 
growth the species are determined. 

These methods have also made possible the cultiva¬ 
tion of pure cultures which are highly desirable with 
all species of commercial value. A pure yeast makes 
possible a saving of thousands of dollars in the brew¬ 
ing industries alone, and some time, let us hope, the 
housewife may be able to buy pure yeast for her bread¬ 
making. 

It was not until 1850 that these organisms were 
studied as plants. Dr. Waldo Burnett, a young phys¬ 
ician of Boston, suggested this and related theories, 
which since his death have been proved. 

Ten years after, these forms were accepted and 
classified by botanists. 

There were many observers and experimenters in 
the field and about 1881 the science of Bacteriology 
was founded. To Louis Pasteur must be ascribed the 
honor of laying its corner-stone, for he first endeav¬ 
ored to cultivate bacteria and yeasts and tried to make 
pure cultures. Upon the foundation thus laid Robert 
Koch built the germ theory of disease. He culti¬ 
vated certain germs and introducing them into the 
bodies of certain animals was able to produce certain 
diseases. He then suggested the four rules which still 


HISTORY OF BACTERIOLOGY 113 

govern all those who set out on the search for the 
germ of any particular disease: 

First, the germ found in any disease must be found 
in every case of that disease. 

Second, this germ must be grown artificially out¬ 
side the diseased body. 

Third, this artificial culture must produce the spe¬ 
cific disease in the body of a healthy animal when in¬ 
oculated into it. 

Fourth, the same species found in the original case 
must be found in the case due to inoculation. 

The discovery of the bacillus of Tuberculosis, of 
Asiatic Cholera, and of Typhoid Fever followed in 
rapid succession. The last fifteen years have been 
crowded with searching investigations and numerous 
brilliant discoveries. 

The debt of the world to these discoverers is in im¬ 
portance second only to that which it owes to the bac¬ 
teria, the molds, and the yeasts. Because the micro¬ 
organisms have been studied so much from the stand¬ 
point of disease, both in food substances and man, their 
beneficent role is often unappreciated. 

SUMMARY 

From the preceding pages may be gathered suffi¬ 
cient information to increase the appreciation of the 
housewife for her many friends among these micro¬ 
scopic plants—bacteria, molds, yeasts—and to put her 
cn her guard against the many that under certain con¬ 
ditions, which she can largely control, will spoil her 


Identifying 

Disease 

Germs 


HOUSEHOLD BACTERIOLOGY 


Dust as 
Source 
of Danger 


Summary 
of Special 
Terms 


114 

possessions or the few that may bring disease to her 
family. 

In general the harmful bacteria and other forms are 
brought into her house as dust, which through some¬ 
body’s ignorance or criminal carelessness, is allowed 
to scatter itself ; dust allowed to collect in dark warm 
places, to be blown about by wind; dust rising from 
dried expectorated matter on sidewalks, floors or fab¬ 
rics, from drainage infected soil, possibly carried to 
the water or food supplies. 

It used to be said that dirt was matter in the wrong 
place. We see now that dangerous dirt is simply a 
certain kind of matter in the wrong place. It is in¬ 
deed, filth , because this dirt' is alive it must not be 
allowed to grow under any conditions which may bring 
harm to man. 

A summary of a few special terms explained in the 
text may serve as a review. 

Fermentation from a physiological standpoint is the 
result of growth in organic matter of a living organ¬ 
ized ferment. 

Alcoholic fermentation is usually brought about by 
yeasts. A few bacteria and molds are found to be 
capable of making weak alcoholic solutions. 

Fermentation is applied to the process when the 
products are desirable or agreeable and non-poisonous. 

Putrefaction is fermentation carried so far or under 
such conditions that the products are undesirable, dis¬ 
agreeable, foul smelling and poisonous. 


SUMMARY 


ii 5 

It is fermentation of substances containing nitrogen 
—putrid fermentation. 

The products of these fermentative changes are 
gases which give odors; acids—lactic, acetic and bu¬ 
tyric ; weak alcohol, occasionally, and ptomaines 
which, when poisonous, are called toxines. 

When putrefaction has ended and the disagreeable 
products have disappeared, the residue is usually harm¬ 
less and inoffensive. If the processes of decomposition 
go on in an abundance of oxygen, decay is usually 
reached without offensive products. 

Sterilization is the removal of all life and is effected 
by steam, dry heat, chemicals, or filtration. 

To remove bacteria, air may be filtered through cot¬ 
ton wool and liquids through unglazed clay or similar 
substances. 

An antiseptic retards or prevents growth. A dis¬ 
infectant kills. 

Some substances are antiseptic or disinfectant ac¬ 
cording to their strength or the conditions under 
which they act. Sunshine is Nature’s free disin¬ 
fectant; light is commonly an antiseptic, and may be 
a disinfectant. Dryness, excess of moisture, salt, 
strong acids, the essential oils, soap, hot water, etc., 
may be antiseptic with some species and disinfectants 
with others. 

Pasteurization , chiefly applied to milk and cream, 
is a process for killing certain germs which cannot 
endure the temperature of 155 0 to 165° F. for twenty 


Decay 


Spores 


Dust 


116 HOUSEHOLD BACTERIOLOGY 

minutes. This destroys the pathogenic and lactic acid 
bacteria. The milk is then safe, that is, does not carry 
disease germs, and will keep longer than ordinary 
milk, but will in time sour because other germs gain 
access to it. 

Properly Pasteurized milk retains the natural flavor 
and its digestibility is more nearly normal than that 
of milk which has been sterilized. 

Because certain species of bacteria form spores 
which are very resistant to the ordinary methods of 
sterilization, it is necessary to repeat the process to 
ensure success. This repeated boiling for three suc¬ 
cessive days is known as Intermittent Sterilization. 

Infected material which would be harmed by thor¬ 
ough sterilization should be destroyed by fire when¬ 
ever possible. It should never be allowed to become 
dry and thereby add its infectious matter to dust. 


The experiments outlined in the text should be per¬ 
formed as far as possible. The whole lesson will be 
far more interesting if observation of them precedes 
the book study. 

The questions should stimulate the application of 
all principles suggested in the text and, wherever pos¬ 
sible, be answered after actual observation of practice 
based on those principles. 

A further knowledge of the whole subject of the 
micro-organisms included in the science of bacteriol¬ 
ogy may be gained by reading the small but interesting 
books named in the bibliography. 




Curd from a good milk. Large, irregular mechanical holes. 



Curd from a tainted milk. Large, irregular mechanical holes; 
small pinho '.es due to gas. 



Curd from foul milk. 

THE WISCONSIN CURD TEST (Over) 






DIRECTIONS FOR MAKING THE WISCONSIN CURD 

TEST 

J. Q. Emery, Dairy and Food Commissioner, Madison, Wis. 

1. Sterilize milk containers so as to destroy all bacteria in 
vessels. This step is very important and can be done by heating 
cams in boiling water or steam for not less than one-half hour. 

2. Place about one pint of milk in covered jar and heat to 
about 98 degrees F. 

3. Add ten drops of standard rennet extract and mix 
thoroughly with the milk to quickly coagulate. 

4. After coagulation, cut curd fine with case-knife to facili¬ 
tate separation of whey; leave curd in whey one-half hour to 
an hour; then drain off whey at frequent intervals until curd 
is well matted. 

5. Incubate curd mass at 98 to 102 degrees F. by immers¬ 
ing jar in warrmwater. Keep jars covered to retain odors. 

6. After 6 to 9 hours incubation, open jar and observe 
odor-; examine curds by cutting the same with sharp knife 
and observe texture as to presence of pinholes or gas holes. 
Observe odor 

7. Very bad milks will betray presence of gas-producing 
bacteria by the spongy texture of the curd and of flavor. 

8. If more than one sample is tested at the same time, dip 
knife and thermometer in hot water before each time used. 

“Normal milk contains practically no organisms but the 
straight lactic acid bacteria. These germs produce no gas and 
no bad odors, but purely lactic acid, and the curd formed 
therefrom is such as is represented in Figure 1. 

“Milk contaminated by the introduction of dust , dirt, fecal 
matter, or kept in imperfectly cleaned cans, becomes fouled 
with gas-producing bacteria that break down the milk sugar 
and so produce gases and usually undesirable odors. . . . There¬ 
fore milks showing the presence of gas or bad odors in any 
considerable degree are milks that have been more or less pol¬ 
luted with extraneous organisms or carelessly handled, and as 
a consequence such milks show a type of curd revealed in 
Figures 2 and 3.”— Dr. H. L. Russell. (For further 
directions, see Farmers' Bulletin, No. 84.) 


TEST QUESTIONS 


The following questions constitute the “written reci¬ 
tation” which the regular members of the A. S. H. E. 
answer in writing and send in for the correction and 
comment of the instructor. They are intended to 
emphasize and fix in the memory the most important 
points in tho lesson. 








HOUSEHOLD BACTERIOLOGY 

PART II. 


Read Carefully.—Place your name and address on the 
first sheet of the test. Use a light grade of paper, write 
on' one side of the sheet only, and leave space between 
answers. Make all -experiments possible and read the 
lesson book a number of times before attempting to 
answer the questions. Answer every question fully. Do 
not be too general in statement. Give details wherever 
they will show your knowledge. 


1. What is the objection to a common comb, drink¬ 
ing cup, etc., to promiscuous kissing on the lips, or to 
spitting on floors or sidewalks? 

2 . What is an infectious disease? 

3 . How does a case of typhoid fever show human 
carelessness and what should always be done to pre¬ 
vent its spread? 

4 . Through what avenues do germs attack the 
body? 

5 . What are some of the means by which the 
healthy body resists bacterial attacks? 

6 . What is a toxine? An antitoxine? A phag¬ 
ocyte ? 

7 . What is an antiseptic? A disinfectant? Men¬ 
tion some of each. 

8 . What disinfectants should the housewife use 
most freely? 

9 . Where do disease germs multiply chiefly ? 

10 . In what ways should a study of dust affect the 
housewife’s (a) choice of methods in cleaning, (b) 




HOUSEHOLD BACTERIOLOGY 

care of food and clothes, (c) standard in house fur¬ 
nishings, (d) admittance of sunlight and air? 

11. Why do dried fruits keep and why do they 
mold or sour when kept in a damp place? 

12. What other antiseptic and disinfecting meth¬ 
ods are used to preserve food? 

13. Do you know any harmful methods of pre¬ 
serving food from the action of micro-organisms? 

14. What objection is there to turning the leaves 
of books with moistened fingers; wetting envelopes 
with saliva; putting money and pencils in mouth, etc. ? 

15. How insure a safe drinking water? 

16. What does healthful dusting of a room re¬ 
quire ? 

17. Explain certain conditions which might pre¬ 
vent bread from rising, (b) why it tastes sour, (c) 
why slack baked bread may mold quickly, (d) why 
bread should cool rapidly, (e) why warm milk 
should not be closely covered. 

18. How may “June flavored” butter be made 
in January? 

19. What especial precautions are necessary to 
prevent infection with (a) tuberculosis, (b) typhoid 
fever, (c) pneumonia? 

20. What have you learned from Household Bac¬ 
teriology which can make better conditions for 
health to yourself and others? 

21. What questions have come to your mind? 

Note .—After completing the test, sign your full name. 


SUPPLEMENT TO 
HOUSEHOLD BACTERIOLOGY 



LOUIS PASTEUR. FATHER OF BACTERIOLOGY 



EXTRACTS FROM THE INSTRUCTOR’S NOTE BOOK 


By S. Maria Elliott, 

Simmons College, Boston. 

Education is not knowledge alone. It is the de¬ 
velopment of the individual, and this development 
should make each person a force in the world. No 
one has a right to keep for himself alone that which 
another needs. This is pre-eminently true in the line 
of scientific education. If the material side of life 
rests upon the principles of natural science, then the 
knowledge of these principles should, as soon as ac¬ 
quired, be put into practice for our own good. But 
this alone is selfishness. It gives us power, but power 
wrongly applied to ignoble uses works havoc. Put 
any newly acquired know ledge into practical use for 
the benefit of humanity and the w r orld is improved, 
while our own lives are enriched. In this w 7 ay, there 
is a subtle truth in someone’s definition of a scientist: 
“The man who thinks God’s thoughts after Him.” 

Our school of Home Economics has enrolled among 
students persons from the Atlantic to the Pacific, from 
Texas to Canada, and even from far-off Hungary. 
Some have the schooling of the grammar grades 
alone, others are in or have passed through colleges 
and even professional schools. Each has had a dif¬ 
ferent experience from every other and each may learn 
from his neighbor. 


117 


ii8 HOUSEHOLD BACTERIOLOGY 

The young girl in the Tennessee mountains may be 
able to give of her experience to the college profes¬ 
sor, while in between and among all grades a common 
bond of interest has been welded because of our com¬ 
mon studies. 

Nor does the enrolled student alone gain knowledge 
from this company of common workers. The in¬ 
structors are not barred out from this feast of good 
things. Through the tests, returned from all quarters 
and by so many persons of varied attainments, stand¬ 
ards of living and rich experiences, the instructors are 
helped to a broader outlook and if, originally they 
were able to write facts which might serve as guide- 
posts in daily living, by this time the index finger 
should assuredly be pointed toward many other helpful 
paths. 

Some one has said that a guide-post is that which 
tells others to go the way in which you will not walk. 
This we will not accept, but wherever any guiding 
finger seems to invite, let us take that path so far at 
least as it serves our purpose and conditions. 

Here are some of the directions in which the stu¬ 
dents of Bacteriology have walked and others may 
follow. The following report from Utah may inspire 
another to do likewise: 

“I have tried to put my newly acquired knowledge 
into practice around the home. For example, I am 
being more careful of our food products to keep them 
from dust. I have used a dampened cloth in dusting 


NOTES 


119 

and have tried to impress upon my mind in practical 
ways the principles of action of these three classes of 
micro-organisms.” 

Definitions are said not to define, but who can im¬ 
prove upon this one from Kentucky? An infectious 
disease is “a disease which is contracted from disease 
germs which make a specialty of this work,” and this 
is as true to facts, although more difficult to read 
aloud, “Bacteria are infinitely small, intensely ener¬ 
getic, enormously prolific protoplasmic micro-organ¬ 
isms.” 

A little knowledge is not always a dangerous thing. 
One woman says, “I thought when I took up the first 
lesson paper that there was nothing in it I should ever 
understand, but now it looks so different.” She had 
seen molds through a magnifying glass, and goes on 
to say, “At any other time I wouldn’t have given it a 
look or thought.” 

A guide-post which points decidedly in the direction 
of success reads*. 

“Thank you more than I can say for the severity of 
your criticisms on the answers I sent. I liked it and 
because of it feel more confidence in the whole course.” 

From Ohio comes this report: “I did find a doctor 
in our town who .... helped me to see things. 

“I had an idea that the contents of the Petri dish 
might be viewed at once. . . . The doctor said 
“Yes, under the focus it would be as large as the state 
of Ohio.” 


120 


HOUSEHOLD BACTERIOLOGY 


Perhaps there are other doctors in other towns who 
would be glad to help the people “to see things.” 

Some inquiring minds met difficulties, however, in 
unexpected places. A student who was “as thirsty 
after information as ever” was discouraged for the 
time being by the fact that she had borrowed a micro¬ 
scope from a physician who was not recognized by the 
“regulars.” The city bacteriologist who had promised 
to furnish “microbes” for examination under said mi-, 
croscope refused “because the Board of Health 
wouldn’t like it,” if their cultures were used by a 
physician “who advertised.” 

Disinfection needs no further explanation to one 
who has before her the picture which she describes in 
this way: “Some years ago while traveling in Mexico 
we had occasion to pass through a yellow fever dis¬ 
trict. Fearing that the disease germs might contam¬ 
inate the oranges peddled at the station by the Mex¬ 
icans and of which we wished to purchase, a member 
of the party sterilized the fruit on the outside by dip¬ 
ping them in alcohol and burning it off immediately.” 
That yellow fever is transmitted only by the sting of a 
certain species of mosquito was not then proved. That 
there may have been other germs on the fruit is not at 
all unlikely and while the alcohol bath may have been 
sufficient, the fire was certainly an ingeniously sure 
method of sterilization. 

A practicing physician among the students says that 
she “wishes every wife, mother and home-maker could 


NOTES 


121 


and would have the advantage of this course of study. 
Scarcely an hour passes in the day when the prac¬ 
tical importance of the lessons is not brought to my 
mind.” 

Having gained an insight into the value of the study 
of chemistry and cleaning, a good Samaritan was 
anxious to help others and used her influence to have 
valuable books on such subjects added to the town 
library. 

A wail comes sounding from Georgia: “The 
housekeeper’s life is one round of activity here not 
only on account of the invisible pests, but those we 
can see, such as roaches, weevils, etc. These may 
abound in the north in the eastern part, but we never 
saw one in Montana.” Happy residents of Montana 
if they have no visible pests, but we have not yet 
heard that in Montana bacteria are absent. 

Mrs. W. finds that strawberries and raspberrries put 
up uncooked “kept perfectly well so far as (yeast) 
fermentation was concerned.” They molded but only 
on the surface. When this surface growth was care¬ 
fully removed, there was no taint present. 

From the deck of a houseboat on the Mississippi, in 
the midst of a cruise of 1,200 miles, comes the state¬ 
ment that there bacteria die, “for even the dirt aboard 
exercises too much to settle down to idleness and mis¬ 
chief.” Fresh air and sunshine—Nature’s best disin¬ 
fectants—should certainly be found on such a vacation 
trip. 


122 


HOUSEHOLD BACTERIOLOGY 


An interested man adds the bit of information which 
may inspire others to experiment, possibly with success. 
He says they “have often—in Kansas—tried to pre¬ 
serve figs by canning them but thus far we have failed. 
Had to preserve them in sugar.” 

An affirmative answer must certainly be given to 
the pertinent question: “Do not tooth brushes and 
wash cloths contain microbes?” They certainly do 
unless carefully cleaned. The former should occasion¬ 
ally have a bath in borax water. The latter should be 
well dried daily in the sunshine, if possible, and fre¬ 
quently boiled. There need not and should not be the 
putrid brush and the sour cloth. The sponge is a very 
difficult article to keep sweet and clean by common 
methods. The cloth is certainly much to be preferred 
from the standpoint of cleanness. 

The suggestion is not a bad one that “gloves be 
worn always while shopping.” We may suggest that 
these gloves might well be washable. 

How much healthier our homes would be if we 
would take the advice of Mrs. W. and “do away with 
the unnecessary ornaments, merely dust collectors 
. . . . dispose of them and train the eye to sim¬ 

plicity and healthful emptiness.” Along the same line 
is Miss G’s decision: “I have been very much 
tempted of late to give up my rugs and mattings and 
use carpets, but I feel now that it would be taking a 
backward step.” It would be better, if it were pos¬ 
sible, to do away with the matting which unless the 


NOTES 


1 23 


dust be wiped off from the surface instead of pushed 
through with the broom, will store much dust under¬ 
neath. 

Miss R. of Illinois has learned that one element in 
“vital resistance” is to keep one’s self in good health, 
“for then my tonsilitis germs wouldn’t have de¬ 
veloped.” This is her decision after having spent a 
part of the “Glorious Fourth” in bed in the study of 
Part II. 

One of our students in Michigan has experimented 
in the sterilization and canning of milk, “using a solu¬ 
tion of salt to increase the temperature of the water.” % 
She found that by repeating this process three succes¬ 
sive days the milk would and did “keep over three 
years and would have kept indefinitely except for an 
accident.” 

An enthusiastic teacher from Canada who “enjoys 
bacteriology heartily,” performed not only the expe¬ 
riments with dust gardens but also numerous others, 
with most satisfactory results. Her enthusiasm and 
success may well be passed along for the benefit of 
others. 

One of her best results in growing molds came from 
a medium of ten per cent prune juice, ten per cent 
gelatine with eighty per cent water. This was ex¬ 
posed for twenty minutes. In a week there had 
grown “about twenty mold colonies” and five of 
bacteria. 

Another garden was made like the above, substitut- 


124 


HOUSEHOLD BACTERIOLOGY 


ing jelly for the juice. In this the bacteria flourished 
better than the molds. One of the gardens which she 
tried was turned to liquid in a week. 

She was fortunate to receive from a bacteriologist a 
pure culture of b. prodigiosus or the “miracle germ.” 
This she planted in the yolk of a hard-boiled egg and 
in a week it had transformed the yolk to a red mass 
mingled with much liquid. This was well covered and 
kept in darkness. She one day found that the hecto¬ 
graph had become a garden of molds and bacteria. 
Under the right conditions it might have been lique¬ 
fied. 

That childen can be readily taught by observation 
is shown by a report from the same teacher. A girl 
insisted that her hands were clean, but a tablespoon 
of the water in which she washed her clean hands 
when introduced into milk proved an efficient aid in its 
putrefaction. “The cooking class never forgot to 
wash their hands.” 

A class of farmers’ daughters found many sugges¬ 
tions for their future care of milk products from va¬ 
rious experiments in the cultivation in milk of the dif¬ 
ferent species which turn it sour, putrid, bitter, etc. 

Such reports as these should stimulate other teach¬ 
ers to interest, to instruct, to educate, by similar ex¬ 
periments, the children under their care. Anything 
which will raise the standard of personal cleanness or 
that of food supplies and general house conditions will 
tend toward health and greater economy. 


NOTES 


12 5 


And so the tests and personal letters continue to 
encourage the instructor and open up many a vista of 
unexpected applications or suggested truths. 

The variety of questions show the great need of the 
study even among those favored with high scholarship 
as well as among those trained in the thorough but 
slower school of experience. 

When many facts of everyday life, of common ob¬ 
servation, are seen to be caused by the growth of omni¬ 
present, invisible plants put into the world as benef¬ 
icent agents, all life becomes more interesting. Such 
study should lead away from foolish or ungrounded 
fear. It should lead to thought and wise action, that 
the danger spots be prevented or removed; that each 
do all in his power to protect not only himself but his 
neighbor. 

How strongly it emphasizes the truth from the great 
poet-philosopher, John Milton: 

“ Not to know at large 
' Of things remote from use, 

But to know that which 
Before us lies in daily life 
Is tne prime wisdom.” 
















» 





























» 




















































SAFEGUARDS OF THE BODY AGAINST DISEASE* 

By T. Mitchell Prudden. 

Author of “Dust and Its Dangers,” “The Story of the 
Bacteria,” etc., etc. 

Among the shibboleths of physicians one of the 
more recent and perhaps the most widely popular to¬ 
day is the word immunity, relating to infectious or 
bacterial disease. The subject holds the floor in the 
learned societies; it crams the medical books and jour¬ 
nals ; it lures the solitary workers in the laboratories 
to long and toilsome quests. At last the layman has 
begun the query as to what it is all about, and how 
the new lore which filters through the magazines and 
newspapers out to him may affect his chance for the 
healthful threescore years and ten which is his birth¬ 
right, but of which he is too often ruthlessly deprived. 

It is really worth while for everybody to know 
something about immunity to infectious diseases. For 
the new doctrines and their practical applications in 
the workaday world are full of promise for the preven¬ 
tion and cure of the infectious maladies, if only the 
public will bear its part with intelligence and zeal. 

The beginning of the story goes back more than a 
quarter of a century, when the notion still lingered on 
that disease was a mysterious something apart from 

*Reprinted from The Outlook by permission. 


127 



128 HOUSEHOLD BACTERIOLOGY 

the body machine, which with sinister intent took pos¬ 
session of our interiors and battled for our lives; or 
was a visitation of Providence about which we might 
not inquire too curiously. Then suddenly we became 
aware that the soil, air, and water, the surfaces of 
plants and of our own bodies were swarming with 
minute, invisible, living beings, some few of which 
were of the greatest importance to man because they 
were capable of inciting serious disorders. By a tech¬ 
nical device of the laboratory it was soon found pos¬ 
sible to secure these invisible plants from their various 
sources, to separate them one from another, and to 
cultivate and study them with as much precision as the 
farmer grows and gathers his various crops. 

Of course at first the few harmful members of this 
newly exploited group of living things cast a shadow 
over all the rest. And we shuddered as the pioneer in 
this new domain of science revealed the thousands 
and tens of thousands of bacteria which we might be 
swallowing with our glass of water or with our bunch 
of grapes. But we were soon reassured, for we were 
told that we had nothing to fear from the rank and 
file of our humble, newly discovered commensals; that, 
on the contrary, they were our friends, without which, 
indeed, the world of life could not long continue. It 
was only the few which we must avoid if we would 
steer clear of tuberculosis, pneumonia, diphtheria, ty¬ 
phoid fever, cholera, and a dozen or so others of the 
uncanny brood of infectious diseases. 


NOTES 


129 


These disease-producing germs the bacteriologist 
soon came to know very well as he grew them in the 
safe purlieus of his laboratories and found out the 
various ways in which they were able to work havoc 
in the delicate mechanism of their earth-neighbor, 
man. Thus the nature of disease became clearer and 
the problems of its prevention and cure definite and 
precise. 

BARRIERS OF THE BODY. 

The healthy human body is safe-guarded in many 
effective ways against the entrance and continued life 
of bacteria and allied organisms. The tough skin 
affords a most impregnable barrier. The nose and 
throat and the tubes leading to the lungs are protected 
with various mechanisms barring the way to many 
germs which dusty air bears in every breath. The 
complex chemical processes in our digestive apparatus 
which convert our\food into building material for 
brain and muscle spell death to the myriads of bac¬ 
teria with which our uncooked foods are mingled. So. 
altogether, our life among bacteria, even those of the 
deadly sort, is usually exposed to little hazard. 

But when the best is said, these minute inciters of 
disease do now and then win their way to the intimate 
recesses of our bodies, producing serious results. The 
measure of their ravages is found in the tables of the 
statisticians, which show that a large proportion of 
all who die fall victims to these invisible foes, and 
that, too, at an age when life holds out its brightest 
promise. 


130 HOUSEHOLD BACTERIOLOGY 

Now let us see how these germs are able to do such 
serious damage in the living body. This body is 
made up of a bony framework, around which various 
tissues and organs are securely and compactly grouped. 
Each one of these tissues and organs is composed of 
tiny structures called cells. The cells are little centers 
of energy stored up from the food we eat and the air 
we breathe—little laboratories in which chemical pro¬ 
cesses of the most subtle character are constantly go¬ 
ing on. And the life of the body is simply the sum 
of the more or less independent but co-ordinated lives 
of the cells which compose it, all acting in har¬ 
mony. * * * 

All these delicate and exquisitely adjusted elements 
of the body are able to adapt themselves to many 
vicissitudes without serious disturbance to that sensi¬ 
tive equilibrium which we name health. We may 
starve them, surfeit them, overwork them, and poison 
them in the most abandoned fashion. But they sway 
back to their respective tasks again when our abuse 
ceases. Unless we go too far; and then they may 
struggle on, but only in the halting, perverted way 
which we call disease. 

Now, what happens when into this happy family of 
cells, each nicely adjusted to the others, and all en¬ 
gaged in their various tasks, living bacteria enter, hav¬ 
ing escaped the outer safeguards ? 

But before we try to discover this, let us brush 
away a few cobwebs. 


SAFEGUARDS OF THE BODY 131 

NATURE OF DISEASE 

We are so accustomed to personify disease, to think 
of it as a visitation of malign forces, and to talk of it 
in terms which belong in the era of superstition and 
personal devils, that clear notions of disease as a 
process, not a thing, are rare indeed. 

Disease is a perverted process of the living body 
cells. Bacteria are not the disease; they are only the 
inciters of disease; nor do they enter the body with 
sinister intent. If the chances of the hour bring them 
to rest among the living body cells, and if the condi¬ 
tions are favorable, they begin to grow, but with just 
as little purpose for good or evil as if they had lodged 
upon the surface of a rotten turnip. 

Many of the bacteria which enter the body do not 
grow at all. The soil is not to their liking, the envi¬ 
ronment is not congenial; they die and are hustled 
off forthwith by certain lowly organized cells—phago¬ 
cytes we call them—which are the scavengers of the 
body, and are ever moving here and there to keep the 
tissues clear and clean. Many bacteria, on the other 
hand, find in the living body conditions suitable enough, 
faute de mieux, for their simple life processes. But 
they are speedily devoured and digested by the scaven¬ 
ger cells, or are killed by destructive body juices, and 
so their tragedies end. 

But there is another side to the story when the bac¬ 
teria which are stranded within the tissues are not 
to be tolerated in a well-organized cell family. Then 
trouble begins. 


132 


HOUSEHOLD BACTERIOLOGY 


We are likely to think that because bacteria are so 
small and lowly they cannot do much. But in fact 
they do a great deal. Their life processes are ex¬ 
tremely complex. They are chemical engines of great 
potency. Out of the food which they assimilate they 
manufacture a host of subtle poisons, some of which 
are stored up in their tiny bodies, some set free into 
the fluids of their hosts. This, in fact, is* the front of 
their offending: the poisons which they elaborate and 
set free damage the cells. 

Sometimes these poisons interfere with the neces¬ 
sary performances of the cells close about them, or they 
harm them, but not irretrievably; or they may kill 
them forthwith. Again, they are carried far and wide 
throughout the body, and the heart is enfeebled, the 
brain palsied, or fever dominates the scene. 

This is the situation, then, when disease-producing 
bacteria get in among the living body cells and begin 
to grow, setting free their powerful poisons. It is 
cell against cell—the well-bred, highly differentiated 
cell of the body against the crude, prolific spark of 
matter way down upon her borderland of life, potent 
only to eat, to multiply, to shed abroad its poison. But 
the weapons of both the combatants are poisonous. 
For we should not permit our sympathetic viewpoint 
to obscure the fact that the fluids and the digestive 
juices which our own cells elaborate are poisons for 
bacteria, quite as much as is their stuff for us. It is 
the old story of the survival of the fittest here in this 


SAFEGUARDS OF THE BODY 


133 


little hidden arena. A new environment is estab¬ 
lished both for the body cells and for the bacteria; and 
what we dramatize as a battle is really only the at¬ 
tempt of each to adapt itself to the new conditions 
furnished by the other. The one which adapts itself 
most readily and completely and quickly wins, by 
survival. 

Infectious diseases, then, are those which are in¬ 
duced by the entrance into the body and the multipli¬ 
cation there of disease-inducing micro-organisms. 
These are most frequently bacteria; but other lowly 
beings, such as yeasts and minute animals called pro¬ 
tozoa, are sometimes to blame. Each of these infec¬ 
tious diseases has its peculiar characteristics by which 
physicians recognize it. These features are especially 
dependent upon the nature of the bacteria which in¬ 
duce them: their ways of growing, the nature of the 
poisons which they set free, their tenacity of life, etc. 
But the body cells have their particular vulnerabilities 
to bacterial poisons, so that in one case it is the nervous 
system, in another the lungs, in another the digestive- 
apparatus, which especially suffers. Moreover, as one 
rose is redder than another, or one aromatic plant 
more pungent than its fellow, so in one case the bac¬ 
teria which gain access to the body may evolve a 
more potent poison than in another, and then the dis¬ 
ease may be of a more virulent type. So also an 
individual may at the time of infection be much more 
susceptible to the ravages of the germ than is usual, 
and thus the victim of a graver form of disease. 


134 


HOUSEHOLD BACTERIOLOGY 


Now we come to immunity. We have seen that, 
under the usual conditions, the body may be capable 
of disposing of bacteria or other microbes which enter 
it by means of its cells or its, fluids, so that the in¬ 
vaders can do no harm. This condition is called here¬ 
ditary immunity—an immunity which is born with us. 
There is a good deal of difference in animal species 
in this respect. For many bacteria which are deadly 
to some of the lower animals are harmless to man, and 
vice versa. So also among the lower animals them¬ 
selves some are susceptible, some not, to the same 
species of bacteria. 

But there is another phase of immunity which we 
must look at a little more closely, called acquired im¬ 
munity. It is a very old observation of the doctors, 
which has become part of the lore of the layman, that 
there are infectious diseases in which one attack, if 
recovered from, protects its victim for a longer or 
shorter period against a subsequent attack. This is 
true of smallpox, measles, scarlet fever and in less 
marked degree of typhoid fever, diphtheria and others. 

Here is a form of acquired immunity secured 
through an experience of the disease itself. In fact, re¬ 
covery from an infectious disease can take place only 
by the establishment of an immunity which did not pre¬ 
viously exist. But this acquired immunity in some in¬ 
stances suffices only for the exigencies of the hour, 
while in others it persists for some time, precluding 
fresh infection. 


SAFEGUARDS OF THE BODY 


135 


In order to understand what has happened in the 
body of a person who has thus acquired immunity 
through a successfully weathered attack of an infec¬ 
tious disease, it will be necessary for us to look at 
some very remarkable achievements of the past few 
years in the prevention and cure of diphtheria. For, 
though the fact of immunity acquired through disease 
has been known so long, no one until recently could 
offer even a plausible conjecture as to the reason for it. 
Among the earlier of the disease-inducing bacteria to 
be discovered, some twenty years ago, was the bacillus 
of diphtheria. This is a little rod-like plant found only 
in connection with this disease, or in those who have 
been exposed to it. It is readily cultivated in the 
laboratory, being very fond of beef tea, in which it is 
commonly grown. 

When a few of these living bacilli from the. culture 
are put beneath the skin of animals, such as rabbits 
or guinea pigs, a fatal disease is induced, essentially 
similar to the disease—diphtheria—in man. 

In the early days of bacteriology it was believed 
that, in order to induce artificially the symptoms of 
an infectious disease, the living germs must be put 
into the body, and grow there. But it was presently 
discovered that if you separate all the germs from a 
culture of the diphtheria bacillus, and introduce the 
beef tea in which they had grown for some time, into 
an animal, you can induce the symptoms of the disease 
just as well as if the germs themselves are put in. 


136 


HOUSEHOLD BACTERIOLOGY 


Thus was revealed the significant fact that bacteria 
may damage the body quite as much by the poisons 
which they elaborate as by their direct presence. 

Now came the next step in the upbuilding of this 
remarkable series of discoveries. It was found that 
if this beef tea in which diphtheria bacilli have grown, 
and which contains the germ-poison, be introduced 
into an animal, at first in very minute quantities, which 
are gradually increased in subsequent doses, the ani¬ 
mal grows more and more tolerant of the poison, until 
at last he sustains with indifference amounts which, if 
given at first, would have been certainly and speedily 
fatal. 

In other words, it was found that by the use of the 
poison alone of the diphtheria bacillus in increasing 
doses, an animal can be rendered artificially immune 
without, having suffered from the disease diphtheria 
at all. 

But now a most incredible thing was discovered. 
It was found that if the blood be drawn from an ani¬ 
mal thus rendered artificially immune, and allowed 
to clot, the yellowish, watery fluid which separates 
from the solid part, and which we call blood serum, 
contains something which, when the serum is intro¬ 
duced into the body of another animal, perfectly pro¬ 
tects him, not only from the poison of the diphtheria 
germ, but from the living germ itself; in other words, 
renders him, too, immune. 


SAFEGUARDS OF THE BODY 


137 


ANTITOXIN. 

This curious something so potent and so beneficent 
was called antitoxin, because it acts by neutralizing or 
abolishing the harmful effects of the toxin—that is, 
the poison of the diphtheria germ. 

No chemist has ever been able to separate antitoxin 
from the blood serum; no man knows its composition; 
but there it is, the heart, it seems, of the mystery of 
immunity. 

One might think that we had found here some re¬ 
markable cure-all in this antitoxin, and that it would 
prevent or cure other infectious diseases. But this 
is not the case. It has no more effect in the preven¬ 
tion or cure of other diseases, such as pneumonia, 
typhoid fever, etc., than so much water. In other 
words, its action is specific. 

The seeker of light in fields relating to medicine 
is rarely free from the consciousness of urgency in the 
solution of his problem. So the moment he found 
that lie could protect the lower animals against the 
ravages of diphtheria which he had artificially induced, 
he turned at once to the possibility of human protec¬ 
tion and cure. And the situation was indeed urgent. 
No disease was more dreaded than diphtheria, espe¬ 
cially in children; the suffering of the victims was 
pitiful, the mortality great. 

The first experiments were made on small animals, 
but if the serum were to be used in children larger 
quantities would be required, so sheep and goats were 


138 


HOUSEHOLD BACTERIOLOGY 


immunized. But these did not furnish enough. So at 
last the horse was tried, and was found admirably 
adapted to the purpose. He lends himself readily to 
the increasing doses of the potent diphtheria poison; 
he is easily rendered immune, and he furnishes without 
especial inconvenience a large quantity of blood. In 
fact, he makes no more fuss about losing blood than 
did the old people along in the early part of the last 
century, who were quite accustomed in the springtime, 
when they felt a bit heavy and had a little headache, 
to drop into the nearest barber shop to be bled. 

The preparation of diphtheria antitoxin has been 
brought to a high state of perfection. The horses 
are first very carefully tested so as to be certain that 
they have no disease. They are well fed and groomed, 
and suitably exercised. At first a small amount of the 
diphtheria toxin is injected beneath the skin. After 
a few days a larger dose is given, and then at intervals 
larger and larger quantities, until at last the horse is 
receiving such an amount in a single dose as if given 
at first would have sufficed to kill not only one but 
many horses. He has not had diphtheria at all, but 
he is now poison-proof—immune. 

■The animal is then bled from the large vein in the 
neck, the greatest care being taken, by cleansing of the 
skin, the use of sterilized instruments, etc., that no 
outside germ shall get into the blood as it flows. This 
blood is set aside in a cool place, and presently, as the 
clot forms, the serum separates in considerable quan- 


SAFEGUARDS OF THE BODY 


139 


tity. This is drawn off into flasks and contains the 
precious life-saving stuff, antitoxin. 

Since no one has been able to separate this anti¬ 
toxic substance from the serum, it is necessary, in 
order to find out how powerful it is—for its virtue 
varies with every horse—to have recourse to quite un¬ 
usual methods. ' It ’cannot be weighed as the druggist 
weighs rhubarb or camphor. But as its value depends 
upon its powers to neutralize the action of the diph¬ 
theria poison in living animals, the test of its strength 
must be made on these. Guinea pigs are usually em¬ 
ployed. It is thus learned how much of the antitoxin 
to be tested is necessary to save the life of the animal 
which has received a fatal dose of the diphtheria 
poison. 

The amount necessary for the protection of a human 
being is larger in such proportion as his weight is 
greater than that of the guinea pig. The saving power 
of each specimen of antitoxic horse serum having been 
thus determined, it is carefully tested to see that no 
contamination has taken place, then it is divided into 
the proper doses, each in a small sealed bottle, and 
sent out upon its mission. 

This antitoxin is not effective if given by the mouth, 
as many drugs are; but it is introduced beneath the 
skin by a small syringe, and is speedily absorbed into 
the body fluids. 

Now, what has been accomplished by the use of this 
new and curious form of medicine ? The mortality 


MO HOUSEHOLD BACTERIOLOGY 

from diphtheria, taking the results the world over and 
in a general way, has been reduced more than 50 per 
cent, and, under the most favorable conditions, full 
75 per cent. I need not dwell upon the significance of 
this beneficent result in the saving of life and in the 
relief of suffering. 

But there is another way in which diphtheria anti¬ 
toxin has been of the greatest value; that is, in the 
prevention of the disease among those who have been 
exposed to infection in families, schools, and other pub¬ 
lic institutions. Under these conditions an injection; 
of the antitoxin beneath the skin has been the means 
of warding off an attack of the disease in groups of 
persons, some of whom without it must inevitably have 

We should be most ungrateful if we failed to recog¬ 
nize the importance of this new relationship which has 
been established between ourselves and our old and 
ever-useful friend, the horse. We make him manu¬ 
facture for us in the department of his interior that 
protective stuff which we could otherwise secure only 
by ourselves sustaining an attack of diphtheria, and 
this, too, with the chances against success. 

We are now prepared to- inquire how this curious 
antitoxin acts in the body to produce these truly mar¬ 
velous effects. Has the body kept secreted all through 
these years of evolution some special mechanism, or 
some chemical potency, by which all of a sudden it 
can protect itself against so subtle and so special a 
poison as this roving bacillus? And if so, do we keep 


SAFEGUARDS OF THE BODY 


141 

on hand in our mysterious insides the latent power of 
protection against all the special forms of disease- 
producing bacteria which wander the earth? How 
does it fit into physiology? Or can we indeed create 
new protective powers in the stress of such varied 
accidents as new infections involve? 

We have seen that the diphtheria bacillus produces 
its deadly effects through a poison which it sets free 
as it grows in the body. In order to understand how 
this poison is rendered harmless, we must know how 
it damages the delicate body cells. So we must go 
back to the cell for a moment. These cells in the 
living body sit in their respective places, and as the 
nutrient fluids pass and bathe them, each of them 
being a powerful little chemical factory, they seize up¬ 
on whatever nutrient molecules they require, and out 
of these build up such new substances as they need in 
their business, whether this be self-nutrition, or the 
storage of energy, or the furnishing of special life- 
stuff for their neighbors. So each cell is armed with 
this power of forming chemical union with the food. 

But suppose something comes along in the body 
fluids with which the cell can and does form the same 
sort of chemical union, but which is not a food; on 
the contrary, damages the cell—that is, is poisonous 
„ or toxic for it. The cell suffers, of course—first, by 
the direct damage, and, second, by the loss of its 
food-securing capacity. The latter it has used up in 
uniting with the poison. 


142 


HOUSEHOLD BACTERIOLOGY 


Now, the cell—so runs the theory—finding itself 
deprived of its food, produces a new and increased 
amount of this food-seizing substance. In fact, in 
accordance with a well-known law in pathology, it 
produces such a surplus of this substance that it is 
cast off into the body fluid. 

But this food-seizing substance, now produced in 
superabundance and cast off, is still capable of uniting 
with the poison which is circulating in the body fluids. 
This it does, and as molecule by molecule the poison 
forms the new chemical union it is neutralized and 
so prevented from coming in contact with the cells, 
where alone it can do harm. This is antitoxic im¬ 
munity. 

Now, if more of this stuff is given off by the cells 
in the emergency than is necessary to render all the 
poison harmless, the excess in the body fluid remains 
there as unused antitoxin. This is the condition of 
the immuned horse. His cells have produced more 
antitoxin than is necessary to protect himself, and 
we draw off some of it in the blood and use it to 
save the child. 

Thus we see that this curious protective process 
is not an incredible anomaly, but that the body cells 
have availed themselves in an emergency as protective 
agencies of those capacities which under normal con¬ 
ditions they use in the assimilation of their food. 

This power of the body to protect itself against the 
poisonous products of bacterial life may be exerted 


SAFEGUARDS OF THE BODY 


M3 


in a similar way in the presence of other poisons. 
Thus certain poisonous vegetable extracts and the 
venom of snakes may be used to secure artificial im¬ 
munity in the horse, with the development of antitoxin. 
In countries where venomous reptiles abound th$ loss 
of life from their bites is sometimes very great; for 
example, in India, where the great cobra slays many 
victims. An antitoxin for snake poison is now made 
which is most effective against the bites of the cobra 
and several other venomous serpents. It is called 
antivenin. Its efficiency for rattlesnake bites has been 
claimed, but recent studies have thrown some doubt 
upon this point. 

Of course as soon as this remarkable diphtheria 
antitoxin was discovered the eager workers in the 
field of preventive medicine at once concluded that we 
were at the dawn of a new day. For if we can so 
effectively control the ravages of diphtheria, why not 
of the other bacterial diseases? So everybody set to 
work to discover new antitoxic sera—of pneumonia, 
tuberculosis, plague, typhoid fever, cholera and vari¬ 
ous forms of blood poisoning, the bacterial excitants 
of which were already known. 

But, unfortunately, these efforts, pursued with the 
utmost zeal and persistence the world over, have thus 
far met with very little success. Antitoxic sera for 
tetanus, or lockjaw, and for some forms of blood 
poisoning, have seemed to be measurably useful. But, 
for the most part, the attempts have failed, except in 


144 


HOUSEHOLD BACTERIOLOGY 


the daily newspaper, for which the discovery overnight 
of a new “serum” seems to furnish an item of per¬ 
petual interest. 

The reasons for this failure are in part evident to 
experts in this field, in part arc still very obscure, and 
are too technical to be entered upon here. But the 
eager and toilsome search goes on wifji such inspira¬ 
tion as is ever his who deals with these urgent prob¬ 
lems of life and death, and at any moment the key to 
the riddle may lie in our hands. 

It would be interesting, did the scope of this article 
permit, to look at the means by which the body pro¬ 
tects itself against infection, not by neutralization of 
poisons, but by the actual destruction of the poison 
producers—the bacteria themselves. Suffice it to say 
that here also, in this bacteria-destroying phase of 
immunity —germicidal immunity, it is called—the body 
does not command new forces or mechanisms, but 
makes use of those which are maintained for its daily 
service, but which in the emergency it wields to new 
ends and with exalted energy. 

OTHER METHODS OF PROTECTION. 

When it was found that it was not possible at once 
to secure antitoxic sera for other infectious diseases 
in the way which had been so successful with diph¬ 
theria, the attempt was made to obtain protection in 
some other way. The leading idea in these researches 
was to find a method of adapting man to pathogenic 
germs without exposing him in the process to the 


VACCINATION 


145 


risks of the disease. Some bacteria seem to produce 
their harmful effects not so much by the poisons which 
they set free as by something stored up in the bodies 
of the getrns themselves. But if the living germs 
are put into the body, they may cause the disease, and 
the very thing to be guarded against might thus be 
precipitated. 

So the attempt was made to avoid this risk by kill¬ 
ing the germs by heat and then injecting these dead 
organisms beneath the skin of the person to be pro¬ 
tected. This method has been practiced on a large 
scale in some countries with the typhoid fever bacillus 
and with the bacillus of the plague. While some meas¬ 
ure of protection seems to have been secured in this 
way, the method has not been very generally adopted. 

There are two other forms of artificially induced 
immunity which we must consider briefly, since they 
belong among the greatest life-saving agencies at our 
command today. I refer to vaccination for protection 
against smallpox and the preventive inoculations for 
rabies or hydrophobia. 

VACCINATION 

First, vaccination to prevent smallpox. If the good 
Dr. Jenner, who more than a hundred years ago did 
some excellent observing and some clear thinking 
about what he saw, and found out how to prevent 
smallpox, could listen to our up-to-date talk about bac¬ 
teria, microbes, toxins and antitoxins, and various 
phases of immunity, he would not understand a word 


146 


HOUSEHOLD BACTERIOLOGY 


of it. But, just the same, he led the way to the prac¬ 
tical banishment through artificial immunity of one of 
the greatest and most dreaded scourges of man. 

It was known in Jenner’s time that those who 
milked cows having sores upon the udder, due to a 
local affection called cowpox, often acquired similar 
sores upon their hands. These soon healed, involving 
only a slight illness. But such persons had become 
partially or wholly immune to the more serious disease 
of man, smallpox. 

Jenner studied this subject carefully and came to 
the conclusion that artificial inoculation with a very 
small portion of material taken from such cattle might 
be practiced on a large scale with beneficent results. 
In spite of much opposition he urged his views, which 
were gradually accepted, until at last the method has 
become almost universal in civilized communities. 

Large and carefully managed establishments are 
now devoted to the preparation of the virus, as it is 
called, by which artificial immunity to smallpox is se¬ 
cured. The slight affection of animals—calves—from 
which the virus is taken is called vaccinia, while the 
disease corresponding to it in man, smallpox, is called 
variola. 

The method now practiced on the large scale is very 
simple. Healthy calves are carefully cleansed and kept 
in clean, airy stalls. The belly is shaved and most 
scrupulously freed from all possible sources of con¬ 
tamination. Into this clean surface, slightly scarified. 


VACCINATION 


147 


is rubbed some of the virus secured from previous 
cases. After a few days this surface furnishes a yel¬ 
lowish, watery material which contains the protective 
stuff. This is gathered and mixed with glycerine, and, 
after careful tests of its purity, is distributed to physi¬ 
cians in small sealed glass tubes. This virus rubbed 
on to a scratched surface of the human skin induces 
a slight sore, sometimes accompanied by a little ma^ 
laise, and then heals. 

By this process the liability to smallpox is very 
greatly diminished, but the protection is reduced as 
time passes, so that revaccination is necessary if the 
fullest protection is to be secured. 

It is certain that smallpox is an infectious disease 
induced by some form of micro-organism. .But the 
exact character of this is still unknown. Attempts to 
cultivate it have thus far failed. It appears that the 
unknown organism suffers diminution in virulence by 
passing through the body of the relatively insuscepti¬ 
ble calf, and in this condition, while incapable of in¬ 
citing smallpox in man, is still potent to establish 
immunity. 

A good deal of opposition has developed here and 
there to vaccination even in recent times. This has 
been based partly upon the fear lest foreign and 
noxious material should be introduced into the body 
along with the virus. But if it be carefully prepared, 
this fear is groundless. While accidents are not im¬ 
possible, the ill effects which now and then appear are 


I 4 8 household bacteriology 

usually due to the handling or rubbing of the little 
wound by dirty persons, against the warning of the 
physician. 

Largely as the result of this form of preventive 
inoculation, smallpox is no longer to be seriously 
dreaded. In fact, in the graphic charts which the 
statisticians make out to show the relative frequency 
of various diseases, the lines showing smallpox are 
so short that you can hardly see them; while it is those 
representing tuberculosis, pneumonia and other dis¬ 
eases of the respiratory system which stretch in most 
disquieting fashion across the page. 

HYDROPHOBIA 

Rabies, or hydrophobia, is one of the most dreaded 
of human maladies, and one whose victims in former 
times no medical skill could save. It is an infectious 
disease, though the micro-organism inducing it is still 
undiscovered. Hydrophobia is commonly acquired by 
man through the bites of rabic animals, in this country 
most frequently the dog. The unknown infectious 
agent is present in the saliva of affected animals. It 
travels along the nerve trunks from the site of the 
bite to the central nervous system, where it especially 
concentrates itself. 

Pasteur, the great master in the solution of knotty 
problems relating to bacteria and immunity, spent 
many toilsome and harassing years in the study of 
the rabic virus and in attempts to devise an effective 
method of protection. He found at last that, although 
he could not isolate the microbe, he could transmit 


HYDROPHOBIA. 


149 


the disease from animal to animal by inoculating into 
the nervous system of the well animal a tiny portion 
of nerve tissue from one which had succumbed. The 
inoculated animals invariably died at a fixed period. 

After a long series of studies which we cannot here 
review, he discovered that if the spinal cord of one 
of the inoculated animals (rabbits) which had died 
be dried in a clean place, it gradually lost its virulence, 
so that whereas at first it invariably killed in seven 
days, day by day it lost its power, so that after drying 
for fourteen days it was quite inert. Given thus a 
virus ranging gradually from the very feeble up to 
the strongest, he saw the possibility of gradually ac¬ 
customing the body to the stuff, so that at last it would 
resist the very strongest. 

This was tried on dogs, and it was found that after 
this gradual adaptation to the virus they became at 
last wholly indifferent to the bites of mad dogs or 
the artificial inoculation of the strongest virus. The 
principle was finally applied to man, with the most 
remarkable and satisfactory results. 

Rabies is peculiar in that a long period usually 
elapses between the bite of a rabic animal and the 
development of symptoms. This period, called the in¬ 
cubation period, is in man on the average from thirty 
to forty days; so that if the preventive treatment be 
instituted without undue delay, there is usually time 
for the adaptation of the subject to the artificial virus. 
This accomplished, the disease does not occur. 


150 


HOUSEHOLD BACTERIOLOGY 


At each laborotary where the treatment for the pre¬ 
vention of rabies is carried on, this material of vary¬ 
ing degrees of potency is kept constantly ready, so 
that as soon as possible after a bite from a supposed 
rabic animal the treatment may be started. The oper¬ 
ation is a simple subcutaneous injection, resulting 
usually only in a slight or temporary local soreness. 
The whole affair is completed within two weeks, when 
all apprehension may be dismissed. No untoward ef¬ 
fects follow the treatment. 

The mortality from hydrophobia before the day of 
preventive inoculation was about 16 per cent. Through 
this treatment it has been reduced to about two-teqths 

The methods of securing artificial immunity to in¬ 
fectious diseases, which we have so hastily surveyed, 
widely different as the details may be, all seem to 
depend upon the same wonderful power of the body 
cells to adapt themselves to harmful conditions by the 
use to new ends of the old physiological capacities. 

The task of the investigator centers largely in dis¬ 
covering the ways in which the body cells may be 
educated to their new responsibilities with safety and 
despatch. 

We seem to be just at the dawn of discovery in this 
newly opened field, and the outlook is of the highest 
promise for the relief of suffering and the prolongation 
of life. 

The various preventive means already devised are 
in the hands of experts and require the greatest care 


SAFEGUARDS OF THE BODY 151 

on the part of those who make the preparations and 
skill and judgment in those who advise and administer 
them. With these things “the man in the street” has 
nothing to do. But it is for him to see to it that no 
fad or ism, no false guides, nor ignorance, nor indif¬ 
ference shall hold him from seeking and following 
wise medical counsel in the face of any of the mala¬ 
dies from which artificial immunity may be secured 
today. Here ignorance is folly, indifference, crime. 

On the other hand, it should not be forgotten that 
underlying all these protective measures is the living 
body machine, which each controls for himself. If, 
through the various phases of unwholesome living so 
largely in evidence today, the machine is lacking in 
vigor, then by so much are the chances of recovery 
lessened when the shadow of disease falls across our 
path. 

Not too much work nor too much play; not too 
much food and drink, but enough; good air and in¬ 
telligent cleanliness in houses, assembly places and 
public conveyances—if these conditions be fulfilled in 
such way and measure as the hygiene and sanitation 
of the day demand, we shall go far to establish our 
birthright to threescore years and ten. And our im¬ 
munity to infectious disease, whether we brought it 
into the world with us, or achieve it under the minis¬ 
trations of the physicians, will most closely confirm 
the promise of science. 




BIBLIOGRAPHY 


53 


BIBLIOGRAPHY 

Bacteria, Yeasts, and Molds in the Home, by II W. Conn. 
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The Story of Germ Life, by H. W. Conn. (35c., postage 6c.) 
Dust and Its Dangers, by T. Mitchell Prudden. (75c., postage 
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The Story of the Bacteria, by T. Mitchell Prudden. (75c., 
postage 6c.) 

Drinking Water and Ice Supples, by T. Mitchell Prudden. 
t.75c., postage 6c.) 

Oui Secret Frirnds and Foes, by Percy Frankland ($1.25, 
postage 12c.) 

Bacteria, by George Newman. ($2.00, postage 18c.) 

Bacteria and Their Products, by G. S. Woodhead. ($1.50, 
postage 14c.) 

Clean Milk, by S. D. Belcher. ($1.00, postage 10c.) 

Rote: The above books may be borrowed by members of 
the School for the cost of postage. 

For Advanced Reading 

A Laboratory Guide in Elementary Bacteriology, by Wm. 
Dodge Frost. ($2.50.) 

Bacteriology and the Public Health, by George Newman. 
($5.00.) 

Immunity in Infectious Diseases, by Metchnikoff. ($5.25.) 
Technical Mycology, by Dr. Franz Lafar, 2 vols. ($8.00.) 
Micro-organisms and Fer mentation, by Alfred Jorgensen. 


154 HOUSEHOLD BACTERIOLOGY 

Government Bulletins 

Free of the Department of Agriculture, Washington, D. C. 

FARMERS’ BULLETINS 

No. 29 Souring of Milk and other Changes in Milk Prod¬ 
ucts. 

No. 42 Facts about Milk (revised). 

No. 43 Sewage Disposal on the Farm and the Protection 
of Drinking Water. 

No. 57 Butter Making on the Farm. 

No. 63 Care of Milk on the Farm 

No. 73 Experiment Station Work — IV, Pure Water. 

No. 84 Experiment Station Work — VII, Cured Test for 
Clean Milk. 

No. 92 Experiment Station Work — IX, Pasteurization 
in Butter Making, etc. 

No 107 Experiment Station Work — XIII, Ropy Milk and 
Cream. 

No. 124 Experiment Station Work — XVII, Soil Inocula¬ 
tion, Distilled Drinking Water. 

No. 155 How Insects Affect Health in Rural Districts. 

No. 162 Experiment Station Work — XXI, Purifying Milk 
by Centrifugal Separation. 

No. 166 Cheese Making on the Farm. 

No. 175 Home Manufacture and Use of Unfermented 
Grape Juice. 

No. 210 Experiment Station Work — XXVII, The Covered 
Milk Pail. 

No. 214 Beneficial Bacteria for Leguminous Crops. 

No. 227 Experiment Station Work — XXX, Clean Milk. 

No. 233 Experiment Station Work — XXXI, Cider Vinegar. 


BIBLIOGRAPHY 


155 


No. 240 Inoculation of Legumes. 

No. 241 Butter Making on the Farm. 

No. 262 Experiment Station Work — XXXVI, Water for 
Table Use. Canning by Intermittent Sterili¬ 
zation. 

CIRCULARS OF BUREAU OF ANIMAL INDUSTRY 

No. i Directions for Pasteurizing Milk. 

No. 19 Factory Cheese and How it is Made. 

No. 52 A Chemical Examination of Various Tubercle 
Bacilli. 

No. 57 Invisible Microorganisms. 

No. 70 Tuberculosis of Cattle. 

No. 83 Danger of Infection with Tuberculosis by Dif¬ 
ferent kinds of Exposure. 

No. 91 Bacillus Microphorus and its Economic Importance. 

REPRINTS FROM YEAR BOOKS 

No. 192 Rabies: Its Cause, Frequency, and Treatment 
(1900). 

No. 221 The Use and Abuse of Food Preservatives (1900). 

No. 262 The Contamination of Public Water Supplies, by 
Algae (1902). 

Bacteria and the Nitrogen Problem (1902). 





SUPPLEMENTAL PROGRAM ARRANGED FOR 
CLASS STUDY ON 

HOUSEHOLD BACTERIOLOGY 

By S. Maria Elliott, Simmons College, Boston 

MEETING I 

(Study pages i - 14) 

Dust and Dust Gardens 

The growth of a dust garden will impress this whole sub¬ 
ject much more vividly than any amount of reading. Each 
member should plant and watch the growth of at least one 
garden. One person might prepare and sterilize the nutrient 
gelatine for the class, distributing in sterilized wide-mouth 
vials or test tubes about two teaspoonfuls to each. Each 
member should sterilize the dish or dishes, melt the gelatine 
by placing the tube in cold water and then heating it, pour 
into the Petri dish, cover, cool, and plant. 

(If not to be had locally, a dozen Petri dishes may be 
obtained through the School for $1.90, a half a dozen for 
$ r. 00, not including express charges. Money will be refunded 
for those returned.) 

Arrange as varied conditions for experiment as possible. 
The following list is only suggestive of interesting sources 
and methods of treatment: 

(a) After sweeping a carpeted room with a dry broom, 

expose five minutes, keep at room temperature, but 
not in direct sunlight. 

(b) Same as above but kept in a refrigerator. 

(c) Same as “a” but shut up in a box. 

(d) Dig out from some corner of stairway or room the dirt 

which was overlooked in cleaning. Pulverize this 
and scatter a little over the jelly. Keep in any 
condition desired. 

(e) Let a fly walk over the media. 

157 


158 


HOUSEHOLD BACTERIOLOGY 


(f) Touch the fingers to the jelly after handling dusty books. 

(g) Touch the jelly with pieces of money or with a bill. 

(h) Take any one of the planted plates. Lay over one-half 

of the jelly a thick piece of black paper or cloth. Put 
the dish in direct sunlight. 

(i) Scrape a bit of the deposit from the teeth and touch 

it to several places on the jelly. 

(j) Rub a few drops of boiled water in the palm of the hand 

and mix it with the liquefied media. 

(k) Take one of the dishes to a public gathering and open it 

for five minutes or more when the audience has been 
seated for a short time. 

Require that each experimenter keep a daily record of 
every change, however minute. At the next meeting let 
these experiments be reported, the gardens shown, and as 
many conclusions drawn as may be feasible, leaving their 
truth or falsity to be proved by further study. 

References: Dust and Its Dangers, by T. M. Prudden. 

Chapters I, II, III, IV. (75c., postage 6c.) 
Our Secret Friends and Foes, by Percy F. 
Frankland. Chapters I —III. ($1. 25, postage 
12c.) 

MEETING II 

(Study pages 17-32) 

Character of Bacteria 

If possible, get some physician to show bacteria under a 
microscope. 

(a) Take some from the dust gardens already planted. 

(b) Take a drop of water from a vase of flowers which has 

stood unchanged for a week. 

Put a wisp of hay in warm water, let it stand for twenty-four 
hours in a warm place, then examine with the microscopa 
a drop of the brownish infusion. 

Make any experiments possible from “Bacteria, Yeasts, and 
Molds,” by H. W. Conn, pages 269-285. 


STUDY PROGRAM 


159 


Perhaps the physician may be able to show some pathogenic 
germs. 

References: The Story of Germ Life, by H. W. Conn. Chap¬ 
ter I. (35c., postage 6c.) 

Bacteria, Yeasts, and Molds, by H. W. Conn. 

Chapters VIII, IX. ($1.00, postage 10c.) 

The Story of the Bacteria, by T. M. Prudden 
Chapters I, II, III, and IV. (75c., postage 6c.) 

MEETING III 

(Study pages 33-46) 

Molds and Yeasts 

(a) Show a sample of moldy bread, cheese, shoe, mildew 

from clothes. 

(b) Generate carbon dioxide as shown on page 43. 

(c) Examine both yeasts and molds under microscope or 

hand magnifying glass. 

(d) Make a small portion of “milk emptins” as described 

on page 6. Note changes which occur during one 
week. 

(e) Mix some bread dough. Put a part in the ice-chest, 

keep an equal part at about 70° F. and a third at a 
much higher temperature, ioo° F. or over. Compare 
results at the end of six, twelve, and twenty hours. 

(f) Pour boiling water on a small bit of yeast cake and use 

this solution for mixing another portion of dough 
which is to be kept at about 70° F. 

References: Bacteria, Yeasts, and Molds, by H W. Conn. 

Chapter II, pages 12-24, and Chapters III, 
IV, V, and VI. ($1.00, postage 10c.) 

(Select a composite set of answers to Test Questions on Part 
I and send them to the School for correction. Report on 
the supplemental work done and the results of the experi¬ 
ments.) 


i6o HOUSEHOLD BACTERIOLOGY 

MEETING IV 

(Study pages 49-62) 

Work of Bacteria 

Fermentation and putrefaction. 

References: The Story of Germ Life, by H. W. Conn. Chap¬ 
ters II III, IV. (35c., postage 6c.) 

Bacteria, Yeasts, and Molds, by H. W. Conn. 

Chapters IX-XIII. ($1.00. postage 10c ) 

Our Secret Friends and Foes, by Percy F. Frank- 
land. Chapters IV, V. ($1.25, postage 12c.) 
See also U. S. Government Bulletins. 


MEETING V 

(Study pages 63-96.) 

Harmful Dust Plants 

(a) Perform the experiments outlined on pages 64-66. 

(b) Boil a pint of milk 15 minutes. Pour into bottle 

which has been boiled in water the same time. Close 
with cork which has also been boiled. 

Pasteurize an equal portion (bottle and cork as above). 
Keep this at about 155 0 F. for 15 minutes. Keep both 
under same conditions. Test each day with blue litmus 
paper. Note first trace of acid. Test by smell and 
note first signs of coagulation. Compare results in time. 
When opening, expose as little as possible to dust. Do 
not lay cork down or touch lower part with fingers. If 
cork is handled or exposed to more dust, boil again. 
While cork is out, lay a clean wet cloth over mouth of 
bottle. 

References: Dust and Its Dangers, by T. M. Prudden. 

Chapters VI, VII, VIII. (75c., postage 6c.) 

The Story of Germ Life, by H. W. Conn. Chapters 
V, VI. (35c., postage 6c.) 


STUDY PROGRAM 161 

Bacteria, Yeasts, and Molds, by H. W. Conn. 

Chapters XIV, XV. ($1.00, postage ioc.) 
Our Secret Friends and Foes, by Percy F. 

Frankland, Chapter VI. ($i. 25, postage 12c.) 
The Story of the Bacteria, bj' T. M. Prudden. 
Chapters V-XIII. (75c., postage 6c.) 

MEETING VI 

(Study pages 96-116) 

Household Applications 

(a) Make out a list on paper of the most common and most 

harmful dust gardens occurring in the household —- 
the dishcloth, refrigerator, waste-pipe, damp floor- 
mop, or any cloths put away in dark closets, uncleaned 
bread boxes, etc. 

(b) Expose small portions of bread, cheese, sauces, meat, 

milk to dusty air. Keep in warm, dark places and 
note time, character, appearance of changes. 

(c) Consider the care of hands, teeth, all parts of the body; 

house, sidewalks, backyard, garbage barrels, etc., from 
bacteriological standpoint. 

References: Dust and Its Dangers, by T. M. Prudden. 

Chapters V, IX, XI, XII. (75c., postage 6c.) 
Bacteria, Yeasts* and Molds, by H. W. Conn. 
Chapter II, pages 24-31; Chapters VII, XIV. 
($1.00, postage ioc.) 

Water and Ice, by T. M. Prudden. (75c., 
/ postage 6c.) 

(Select answers to Test Questions on Part II. Report on 
supplemental work and experiments.) 

. - \ • »; . U ' 



THE BACTERIA SCARE* 

By Mary Hinman Able 

There is a rare form of insanity known to physicians 
in which the patient is forever washing his hands and 
fancying that he is polluted by every contact. A few 
years ago when we were at the beginning of our fight 
against tuberculosis, typhoid fever and other diseases 
that may be carried in various forms of filth, it 
seemed that a mild epidemic of this form of insanity 
would be a blessing to any community, as it would 
insure the clean hands which must be insisted on if 
we are to have clean food. However, when one sees 
the wholesale and often unwarranted application of a 
little knowledge of bacteria to every phase of life one 
is thankful for all the existing sanity and desirous of 
its extension. For in the wake of every reform is 
found the trail of the extremist. The Journal of the 
American Medical Association calls attention in a late 
issue to certain statements in a book entitled Good 
Health and How We Won It, by Mr. Upton Sinclair 
and Mr. Michael Williams. It seems that the writers 
recovered their health by decreasing the amount of 
their food and omitting meat entirely. We do not 
hear as a reason that these gentlemen felt that they 
were approaching middle life when just this change 
in the diet has frequently been recommended by 
physicians, though for reasons unconnected with 
bacteria; they say they have abandoned eating of 
meat because of the great numbers of bacteria that 
it contains, there being, it is claimed, hundreds of 
millions of bacteria in different cuts of beef steak and 
several varieties of sausage. 

* From the Journal of Home Economics. 

162 


THE BACTERIA SCARE 


1 63 


It is said that every form of error maybe traced to 
faulty logic; here the trouble seems to be that the 
premises are false. “Meat contains many bacteria. 
All bacteria are harmful, therefore, etc.” The inves¬ 
tigators do not state the kind of bacteria nor the way 
they came to be present in the meat, and evidently 
they believe that meat in and of itself is naturally 
and normally laden with these minute forms of life. 
As a matter of fact though results of a different 
character have been reported not infrequently, care¬ 
fully made and carefully controlled laboratory work 
with all precautions taken has shown that the raw 
flesh of healthy animals is stirile, and only in certain 
animal diseases is bacterial life present in the tissues. 

All living things, both plants and animals, are sub¬ 
ject to bacterial diseases, but if bacteria are found on 
raw or cooked meat from healthy animals it is safe 
to say that they were lodged there by passing air 
currents just as they are lodged on any other food 
thus exposed. Rightly interpreted then, the labora¬ 
tory experiments indicate that all foods should be 
protected from accidental contamination by bacteria, 
as harmful species may be present among them, not 
that meat should be excluded from the diet because 
bacteria happen to be found on it. 

A very few bacteria, not more than 50 or 60 
species, are known to be harmful, many are known 
to serve a useful function and it is thought that some 
varieties may even prove to be necessary to the 
digestive processes. The intestinal tract of man 
swarms with bacteria, and the experimenter has 
never been able to free from bacteria the digestive 
tract of an animal that has once lived under normal 
conditions. Of the foods we eat there are absolutely 
none free from bacteria, if we except cooked food 


164 HOUSEHOLD BACTERIOLOGY 

fresh from the fire. The purest milk obtainable for 
the table contains thousands of bacteria to the cubic 
centimeter, while commercial milk may have many 
millions. Buttermilk and other forms of acid milk 
also contain correspondingly large numbers. Many 
hundreds jof these harmless bacteria are known and 
named, while the harmful or pathogenic bacteria 
number only a few score. It is these few malevolent 
microbes that must be avoided, and hence all tho 
precautions we have -adopted as to cleanliness in 
hospital, market, dairy and kitchen. But if life is to 
be worth living we must learn where these objection¬ 
able varieties come from in order to concentrate at 
the proper place our use of that eternal vigilance 
which is the price of health. 

Here are a few suggestions. Human contact with 
food is probably the greatest source of danger. If a 
piece of dry bread fall on the floor of a clean private 
house the bacteriologist teils us it might be picked up 
and eaten with impunity. Not so if this bread were to 
be dropped on the floor of a trolley car, especially in the 
old days when expectoration was common. The 
driver’s hand which grasps the top of the milk bottle 
which he delivers may leave bacteria there and the 
bottle should be washed before the milk is poured 
out. The diminishing of the number of bacteria in 
our food by the practice of cleanly habits (and no one 
of these habits is more important than the thorough 
washing of the hands before handling and preparing 
food and before meals) is recommended by all hygien¬ 
ists ; but there should be no morbid fear of the con¬ 
sumption of foods that have been the dependence of 
the race since the dawn of civilization and before, 
simply because we do not ordinarily eliminate from 
them every trace of bacterial life. 


INDEX 


Acetic acid, sugar changed to, 
61 

Acid, butyric, 62 
Acids as preservatives, 72 
Acquired immunity, 94, 134 
Agar for dust gardens, 10 
Alcoholic fermentation, 114 
Alexines, 93 
Animalcules, 109 
Antiseptics, 65 
Antitoxin, 94, 137-144 
diphtheria, 95, 138 
Artificial immunity, 94, 136 

Bacteria, 16-32 
as scavengers, 48 
classed as plants, 112 
definition of, 16 
disease producing, 75 
effect of cold on, 90 
excretions of, 18 
experiments with, 64 
food of, 20 
forms of, 17 
growth of, 22 
harmful, 63 
in cheese making, 60 
in coarse meals, 45 
in “eyes” of potato, 45 
in ice, 85 
in milk, 14 
in school rooms, 107 
liquefying, 74 
method of study of, 112 


natural home of, 30 
nitrifying, 51 
on dust particles, 97 
secretions of, 31 
size of, 23 
structure of, 17 
useful, 47 
with flagella, 27 
work of. 47, 54 

Bacteriology, history of, 109- 

113 

lessons for children, 124 
Barriers of the body, 129 
Bed-making, 102 
Blood poisoning, 91 
Body, barriers of the, 129 
Boiling clothes, necessity for, 

30 

Bread, baking, 45 
leavened, 6 

Breeding ground for germs, 77 
Brushing clothing, 106 
Burn infected material, 116 
Burning sweepings, 104 
Butter bacteria, 55 
bad flavors in, 58 
making, 55 
Butyric acid, 62 

Canned goods, 70 
Carelessness, criminal, 83 
Care of discharges in disease, 79 
Of plumbing, ro6 
of refrigerator, 29 


165 



i66 


HOUSEHOLD BACTERIOLOGY 


Cause of lockjaw, 80 
Cheese, 59 

molds in ripening, 59 
Cider vinegar, 60 
Clean eggs, 73 
Clean milk, 14 
Cleaning school rooms, 107 
Cleanness, sanitary, 108 
Clothing, brushing, 106 
Colonies of bacteria, 12 
of dust plants, 10, 15, 16 
Color of mold spores, 38 
Common methods of preserv¬ 
ing food, 68 

Communicable diseases, 75 
Compound microscope, no 
Compressed yeast, 43 
Contamination, sewage, 82 
Covering food, 104 
Criminal carelessness, 83 
Crops, rotation of, 53 
Cultures, solid, in 

Deadly dish-cloths, 106 
Deaths from lockjaw, 80 
Decay, 115 

Diphtheria antitoxin, 95 
bacillus, 135 
Disinfectants, 65 
nature’s, 98 

Disinfectant, sunshine as a, 25 
Disinfect soiled articles, 79 
Disease, care of discharges in, 
79 

from molds, 36 
germs, 75-86 

germs, effect of light on, 83 


germs, identifying, 113 
germs, origin of, 77 
nature of, 131 
producing bacteria, 132 
Diseases communicable, 75 
infections, 133 
specific germs of, 76 
Drying food, 70 
Dust, 1-7 

movements of, 4 
ordinary, 5, 13 
particles, bacteria on, 97 
plants, 15 

plants in refrigerator 28 
plant.*}, life work of, 63 
sources of danger, 114 
Dusters, washing, 104 
Dust-garden out of doors, 73 
plot, the, 7 
Dust-gardens, 7-14 

photographs of, 1,12, 99, 
r °3, 105 

planted after sweeping, 98 
soil for, 13 

Dusting, rules for, 104 
time for, 100 
Dust-proof room, 2 

Effect of antitoxin on the body, 
140 

of cold on bacteria, 90 
of gastric juices on bacteria, 
87 

of light on disease germs, 83 
of poisoning, 92 
of sunlight on disease germs, 
26 


INDEX 


167 


Eggs, clean, 73 
Epidemics of typhoid, 81 
Essential oils as preservatives, 
7 2 

Excretions of bacteria, 18 
Experiences of students, 119- 
124 

Experiments in hospitals, 100 
with bacteria, 64 
with dust, 7 
with yeasts, 42 

Extracts from the Instruct¬ 
or’s Note Book, 117-125 

Favorable conditions for 
germs, 76 
Fermentation, 114 
early theory of, no 
processes, 53 
products of, 115 
Film-forming bacteria, 22 
Filtered water, 85 
Filters, porcelain, 84 
Fission reproduction, 21 
Flagella, bacteria with, 27 
Food, covering, 104 
of bacteria, 20 
Forms of bacteria, 17 
Formation of pus, 90 
Fungi, bacteria classed as, 23 

Gas produced by yeast, 44 
Gastric juices, effect on bac¬ 
teria, 87 

Germ, definition of, 16 
Germs, breeding ground for, 7 7 
disease, 75-86 


pathogenic, 66 
resistance of body to, 86 
Growth of bacteria, 22 
of dust-gardens, 11 
of mold, 33 
of yeast, 40 

Harmful bacteria, 63 
preservatives, 69 
Health, definition of, 88 
History of bacteriology, 109- 
Ir 3 

Hydrophobia, 148 
Ice, 85 

Identifying disease germs, 113 
Immunity, 92, 134 
artificial, T36 
natural, 93 

Importance of bacteriology, 3 2 
Infected material, burning, 116 
Infection by oysters, 82 
method of, 78 
sources of, 86 
Infectious diseases, 133 
Ingredients of dust, 4 
Inoculating the soil with bac¬ 
teria, 52 

Intermittent sterilization, 65, 
116 

June butter, 55 

flavor bacterium, 56 

Koch’s theory, 111 

Laboratory study of bacteria, 

' 

Lactic acid, production of, 14 


i68 


HOUSEHOLD BACTERIOLOGY 


Leavened bread, 6 
Leucocytes, 88 
Life, spontaneous generation 
of, 109 

work of dust plants, 63 
Liquefying bacteria, 74 
Lockjaw, cause of, 80 

Making antitoxin, 95 
Meadow tea, no 
Metchnikoff’s theory, 93 
Meteoric dust, 3 
Method of infection, 78 
of study of bacteria, 112 
Microbe, definition of, 16 
Micro-organisms, 16 
Microscope, compound, no 
Mildew, 6, 37 
Milk, bacteria in, 14 
clean, 14 
Pasteurized, 67 
souring of, 13 
Mold, reproduction of, 33 
spores, 35 

Molds, 6, 33, 39, 59 
in ripening cheese, 59 
work of, 36 
Moldy houses, 38 
Movement of bacteria, 26 
Movements of dust, 4 
Mustiness, 37 

Natural home of bacteria, 30 
immunity, 93 
Nature of disease, 131 
Nature’s disinfectants, 96 
Necessity of dust, 2 


Newman’s theory, 93 
Nitrifying bacteria, 51 
Nitrogen traps, 52 
Nutrient media for dust-gar¬ 
dens, 13 

Opposition to vaccination, 147 
Ordinary dust, 5, 13 
Origin of disease germs, 77 
Oxygen, relations of bacteria 
to, 24 

Oysters, infection by, 82 

Pasteur’s theory, 95 
work of, hi, 148 
Pasteurization, 66, 115 
Pasteurized milk, 67 
Pathogenic germs, 66 
Personal responsibility for 
sanitation, 108 
Petri dish, 7 
Phagocytes, 88 
Photograph of dust-gardens, 

1, 12, 99, 103, 105 
Planting dust-gardens, 10 
Plants, bacteria classed as, 112 
Plumbing, care of, 106 
Poisoning, blood, 91 
effects of, 92 
Polluting water, 83 
Porcelain filters, 84 
Precautions to avoid germ in¬ 
fection, 79 

Preparing soil for dust-gar¬ 
dens, 9 

Preservatives, 72 
Preserving food, 68 


INDEX 


Prevalence of dust, i 
Production of lactic acid, 14 
Products of fermentation, 115 
of yeast growth, 40 
Protoplasm, 17 
Pus, formation of, 90 
Putrefaction, 12 

Rabies, 148 

Refrigerator, care of, 29 
Relations of bacteria to oxy¬ 
gen, 24 

Removing dust, 104 
Reproduction of bacteria, 20 
of mold, 33 

Resistance of body to germs, 
86 

of spores, 28 
Ripening cheese, 58 
Roquefort cheese, 59 
Rotation of crops, 53 
Rules for dusting, 104 

Safeguards of the body against 
disease, 12 7-151 
Salt as a preservative, 72 
Sanitary cleanness, 108 
Sanitation, 96-108 

personal responsibility for, 
108 

Scavengers, bacteria as, 48 
School rooms, cleaning, 107 
Secretions of bacteria, 31 
Settling of bacteria and molds, 
98 

Sewage contamination, 82 
Shape of bacteria, 17 


169 

Size of bacteria, 23 
of yeast, 39 

Soil for dust-gardens, 8, 13 
Soiled articles, disintect, 79 
Solid cultures, 111 
Source of dust, 3 
Sources of infection, 86 
Souring of milk, 13 
Specific germs of diseases, 76 
Spoiling, 71 

Spontaneous generation of 
life, 109 
Spores, 116 
mold, 35 
of bacteria, 27 
of yeast, 39 
resistance of, 28 
Starters, 57 
Sterilization, 115 

intermittent, 65. 116 
Structure of bacteria, 17 
of yeast, 39 

Sugar as a preservative, 70" 
changed to acetic acid, 61 
Summary, 113 
of terms, 114 
Sunlight, effect on disease 
germs, 26 

Sunshine as a disinfectant, 25 
Sweeping, 97 

dust-gardens planted after, 
98 

Sweepings, burning, 104 
Symptoms of poisoning, 92 

Temperature for yeast growth, 

41 


170 


HOUSEHOLD BACTERIOLOGY 


Terms, summary of, 114 
Tetanus, 80 

Theories of vital resistance, 
88 

Time for dusting, 100 
Toxins, 93 

Typhoid, epidemic of, 81 
infection by milk, 81 

Useful bacteria, 47 

Vaccination, 94, 145 
opposition to, 147 
Vinegar, 60 

Vital resistance, theories of, 87 
Wandering cells, 88 


Washing dusters, 104 
Waste of nitrogen, 51 
Water, filtered, 85 
polluting of, 83 
Work of bacteria, 47-54 
of leucocytes, 88 
of molds, 36 
of Pasteur, 111 

Yeast, 39 

compressed, 44 
generating carbon dioxide, 
43 

Yeasts, effect of cold on, 42 
experiments with, 42 
Zooglea, 22 





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